Basic editing

In this part of the documentation I will guide you trough the basics of editing in LDCad. So after reading this page you should be able to create your own simple LDraw models, e.g. a simple house or a small car etc. I will be assuming you have read the GUI Introduction chapter first, and therefore are (somewhat) familiar with the color and part bin area's.

Starting a new model

You can start a new model at almost any time by opening the file menu (top left of the screen by default) and then click its "New model" item. You can also start a new model from the getting started window shown whenever there are no open files.

Right after you start a new model you will be presented by the "Edit header" dialog. This can be used to input some info about the model. At this stage only the "author" field is of any real interest so type your full name in its field. Next you can close the dialog by pressing the 'Ok' button.

The first time you close the header dialog with an filled out author field you will be asked if the given name should be used as the default for all future models. You usually want this so click "yes" when asked.

After all that you will now be presented by an empty editing area in which you can start building something groundbreaking. The screen should look something like the picture below:


In all four corners of the editing area you will find something which control a certain aspect of the building process.

  • Top left shows the current and total number of building steps in your model. Clicking it will open the main step management menu.
  • Top right shows the LDraw file name. When you move your mouse over it it will extent into the session control panel.
  • Bottom left shows the current 3D orientation, this is called the editing compass. When you move your mouse over it, it will zoom into a larger version showing additional grid and view oriented settings and information.
  • Bottom right shows an 'I' icon, this zooms into a panel with model statistics when you move your mouse over it.

The editing compass and stepping menu will be discussed in detail below. The session panel will be discussed elsewhere as it isn't really needed while working on a simple model like the one we'll be working on in this section of the documentation. The "I" (information) icon explains itself, feel free to move your mouse over it now and then to see how many bricks you've used already etc.

Bin preparations.

When working on any new LDraw model it is good practice to first setup the color and part bin views in a convenient way. We discussed the essence of the two bins in the GUI Introduction, feel free to revisit that before continuing.

Luckily this won't be needed for the color bin often as there aren't that many groups to choose from. Lets set view 1 to "solid plastic", view 2 to "Transparent", view 3 to "Rubber" and view 4 to "Metallic".

Choosing groups for the six views in the part bin will greatly depend on the kind of LEGO model (e.g. Technic of Creator) you will be working on. For this example we will be working on a small house.

So lets set view 1 to "Plain bricks", reachable by clicking the below sequence of cells starting at the bin's root.

icon  =>  icon  =>  icon

View 2 would probably be most useful displaying plates, so lets set it to "Normal plates", reachable by:

icon  =>  icon  =>  icon

View 3 might be handy pointing at "Sloped bricks", reachable by:

icon  =>  icon  =>  icon

And as a house needs windows we'll be pointing view 4 to the "Windows" group, reachable by:

icon  =>  icon  =>  icon

Next we could point view 5 to the "Sorted" root group and navigate it further when parts not listed in one of the other views are needed.


Last we set view 6 to the special "Search" group, reachable by clicking the below cell at the bin's root.


This group is needed when trying to find not often used parts without having to go all around the bin tree. To search for a part type a keyword in the search groups filter like shown in the GUI introduction page.

With the bins set to our liking, it is time to finally start building something.

Basic brick placement.

NOTE: Although LDCad has part snapping support, I would like to first walk through grid based editing as it's important to understand grids in order to take full advantage of part snapping.



Building a LDraw model is pretty much the same as building a real LEGO model, you just add one brick at a time. The only difference is with virtual LEGO you have an unlimited supply of bricks in a multitude of colors.

In order to add a brick to the model you first select the color you want the new brick to use. You do this by using the color bin's color wheel. Let's select red so we can start building a wall for our little house. With the color set you go find the brick you want to add to the model in the part bin.

Lets locate the plain 1x4 LEGO Brick for our wall. We pointed part bin view 1 to plain bricks so make sure it's the current view. Next, while the mouse cursor is inside the part bin, use the mouse wheel to scroll down until you spot the 1x4 brick. Click the brick and while holding down the left mouse button move it inside the editing area.

When the brick enters the editing area you'll see something like the picture above. The grid visualizes the current editing (placement) plane and the longer blue and red lines represent the center of that plane. The small window at the bottom right displays the bricks current location in 3D space. Don't worry too much about those numbers for now, just place the brick anywhere in the center by releasing the mouse button.

NOTE: I'm assuming you didn't rotate the scene before placement, if you did so it might be you seeing a different orientated editing plane (e.g. horizontal instead of flat). If so don't worry just place the brick anywhere in the center.

After you let go of the brick the rendering will change again, the grid will be gone and an umbrella like pin will now stick out of it like in the picture at the right. This is the main selection manipulation tool called the editing pin. It will always be perpendicular to the current editing plane as it is used to move and/or rotate the selection in relation to it. By default the editing pin will be in rotation mode indicated by the big disk on top of it.

The editing plane orientated approach used in LDCad will always limit interaction to two of the three building directions in virtual space. As a result your view upon the model is split into three, namely: "Left/right (or Sides)", "Top/Bottom" and "Front/Back". These are therefore the possible editing plane orientations. Which mode is active currently mainly depends on the scene (camera) rotation. This (optional) feature tries to guess the direction in which you want to add something next and sets it for you automatically.

If you need a certain view upon the model using a different editing plane then the one suggested, you can do that by manually switching to one of the other modes. This is done by using the editing compass in the left bottom corner (I'll get into the editing compass in detail below) or by using the three hotkeys assigned for them. These are: "t" (Top/bottom), "s" (Sides) and "f" (Front/back). Do note the mouse cursor has to be inside the editing area for the hotkeys to respond.

Before continuing lets fist discuss the camera system of LDCad, as it's very important during the building process to have a good view upon your model.

The camera system.

LDCad uses a trackball oriented camera system as the default. This means you can rotate the view in any direction possible without it suddenly starting to behave different or lock into itself (called a gimbal lock).

The easiest way to understand the trackball approach is by imagining a big beach-ball stuck inside the editing area rectangle. While rotating you grab it somewhere on its curve and while dragging it will spin into the direction you are moving the mouse. So the starting position of rotations is very important while using this camera system.

To see what I'm talking about just left (or right) mouse button click anywhere on the background of the editing area. Then while holding down the button move the mouse for a bit before releasing it again. Do this using different starting positions to see the way it affects the rotation direction.

Some people really can't get the hang of, or just don't like, this kind of camera system. For this reason there is an alternative camera mode available inside LDCad. This is called the "Spin" mode which will limit the rotation to a turntable like motion. This mode can be set using the editing compass as discussed below. However I highly advise putting some time in using the trackball mode first, as it is very powerful once you get used to it.

Rotating alone isn't enough when working on a model, sometimes you need to move around a bit. This can be done by holding down the shift key while holding down the left (or right) mouse button. While doing this mouse movement will shift the camera to left/right/top/bottom in relation to the current screen orientation. You can also shift the camera around in relation to the current editing plane, this is done by also holding down the ctrl key. Often you'll need a shift in order to concentrate on the current selection, this can be done in one motion by pressing the "c" (Center) hotkey.

Both rotation and movement can be done using either the left or right mouse button, the difference lies in the right button ignoring the model while the left one will select bricks if not clicked on the background.

The last camera control is the zoom, which will determine how much of the model is in view at the same time. Zoom control is done by rotating your mouse wheel. Forwards will zoom in, and backwards will zoom out. You can reverse this if needed using the "prefs/editing" menu. Holding down the ctrl key while zooming will make it use smaller steps. And to fit the whole model inside the view in one go you could also press "z" (Zoom).

During zooming you'll also notice the location of the mouse influences things as by default whatever is below the mouse will stay below the mouse no matter where you point it. This is called "Zoom to cursor" meant to give the user more control over zooming, you can also (mis)use this to do camera movements, e.g. zooming in at the left of the screen directly followed by zooming out at the right side. This will move the view to the right. If you don't like the zoom to cursor feature you can select a different zooming kind using the "prefs/editing" menu.

Above might be a lot to get used to, so feel free to play around using the camera for some time. After you are comfortable using these controls continue building the little house below.

Basic brick placement, continued.


Before we can add a second brick to the model we need to make sure the editing plane is currently set to "Top/Bottom". So make sure the editing pin is pointing up by rotating the camera around or using the "t" (Top) hotkey.

Now we can add a second 1x4 brick near the first one to create a corner of our house. So lets drag one into the editing area from the part bin, just like before. Place it somewhere near the existing brick. Next we need to rotate the brick before aligning it with the other brick. This can be done using the editing pin's rotation mode. As this is the current mode click anywhere on its disk, and while holding down the mouse move you mouse. This will cause the selection to rotate as indicated by a small label containing the current rotation angle. Move it so it says "90 deg" (or "-90 deg") and then release it.

The brick will now be orientated like we want but it's still at the wrong place. You can move it by clicking it and dragging it very similar to adding a new brick. You can also use the editing pin in "move mode" for more precise movements. You put the editing pin in move mode by clicking the center "cross" icon above the disk. Doing so will replace the disk with a cross of arrows.

The editing pin in move mode can be used to move the selection in three different ways on the current editing plane. Clicking and holding the center of the crosses will move it freely around, while clicking and holding one of the arrows will move it limited to a single direction. Use the center of the cross to move it so it makes a corner together with the other brick. Try to position the brick like shown in the picture at the left.

As you will need to rotate and move stuff around a lot there are hotkeys available for choosing either mode, namely "r" (Rotate) and "m" (Move).

You might have noticed the editing pin has a third icon / mode. That mode is used to change the (rotation) center of the current selection. which might be needed when rotating something in relation to something else or around an alternative origin. Elsewhere in the documentation this mode will be very handy but for now we won't be needing it, so you can ignore it for now.


An alternative, easier, way to the above is to rotate a new brick before placing it using the arrow and pageup/down keys. Lets use that method to add a third brick to the house. Drag one into the editing area again but don't release it just yet. As you can see the new brick has the same orientation as the previously placed one. So we could continue the wall in the same direction but that won't do for a rotation demonstration so lets add it to the first bricks direction instead.

While holding a new part or selection in "mid air" the arrow keys will rotate them in steps of 90 degrees. Which axis they rotate around depends on the current camera view in such a way that left/right rotate in a logical direction. So if your view upon the part is mainly from the front the left/right button will rotate it left/right around its vertical (or UP) axis.

In this situation the Up/down arrows will rotate around the horizontal axis and if needed you can use the page up and down keys to rotate around the depth axis. If you hold down the ctrl key while using any of these keys rotation will use steps of 45 degree instead of 90.

You can use the home key to reset the orientation of the new brick to its base state. It is recommended (especially while using part snapping) to do this now and then, even when not needed, as it also help prevent rounding errors in (very) big projects. These "errors" are visible in the source window discussed elsewhere.

Try to rotate the brick so it connects to the first placed brick and once you got it oriented like needed put it at the wanted location. This should give you something like the picture at the right.


Even easier than using the arrow keys is first selecting a brick already in the wanted orientation before adding a new brick. This is because LDCad will always use the last used orientation (and color) for newly added parts. You select a brick simply by left clicking on it indicated by its edges changing color and the editing pin jumping to it. You can deselect it again by clicking it again or by using the esc key while a selection is active.

Once selected you could drag the next brick into the model but if the next needed brick is also a 1x4 one it is much easier (and easier on the wrists) to use the ins key instead. This will insert a new brick of the same type as the last used one. The last used brick, in this case the one we just selected, is called the "working part". You can also change the working part by selecting (and not dragging) a part in the bin indicated by the green rectangle.

Also handy to know might be how to remove a brick from your model, which is done using the del hotkey while the unwanted brick is selected. If you want to remove a brick because you added a wrong one it could also be handy to replace it while keep using the current location/orientation. This can be done by double clicking a different brick in the part bin.

Use any of the above techniques and try to continue the house model until it looks like the picture at the left. This will complete the first layer of bricks. Do note the two 1x2 bricks to make room for the door.

A single complete brick layer is often the end of a building step in official LEGO booklets. So lets start a new building step inside our model too. This can be done in several ways, the easiest way is using the hotkey ctrl+ins or the toolbar button. After using the hotkey or clicking the button the label in the top left will change from "Step 1/1" to "Step 2/2". This indicates you are currently working on step 2 of 2. Below I will go into the building steps a bit more as we will have more steps by then.


Up to now we have been building at the same level using the top/bottom editing plane. But with the foundation finished we need to start a second layer. This is done by selecting the "Sides" or "Front/Back" editing mode using their hotkey ("s" or "b"), or simply rotate the scene until the program selects it for us.

Lets start the second layer by adding a 1x1 brick left from the door opening while the editing plane is set to front/back. To make sure a new brick is added at the same depth coordinate you first select the existing 2x2 brick as LDCad will use the last used "Dead coordinate" for a newly added brick. Drag a 1x1 brick out of the bin and try to place it above the 1x2 one. As you can see the grid is now orientated vertically in extension of the bottom 1x2 brick like in the picture at the right.


Next we add another 1x1 brick to the right side of the door and a 1x4 one besides that one. The 1x4 you can "copy" using ins from the one below it. Complete the second layer on your own, just remember to choose the editing plane, and currently selected brick wisely. Also note once you got both a 1x2 and a 1x4 brick at the second level you have the option to return to the Top/bottom editing plane and add the remaining bricks by using them as working parts / orientation / dead coordinate. If needed you can always rotate them using the arrow keys afterwards.

You can also copy multiple bricks using the ins key by selecting more then one brick at a time. This is done by holding down the ctrl key while left clicking additional bricks. ctrl can also be used to remove bricks from the selection by selecting ones that are already in the selection. For example you could use this to copy the left wall to the right side while using the top/bottom editing plane.

While "cloning" a multi selection it can also be rotated like any normal part drag. This gives you the option to rotate the copied left side bricks 180 degrees before placing them at the right side. This to create a nicer "seam" layout. All this should give you something like the picture to the left.

This completes the second layer so lets add a new building step again by using ctrl+ins, this will change the label in the top left into "Step 3/3".

At this point we'll pause the building for a while to get you up to speed with generic "Building step" usage and the "Editing compass".

Building steps

A very important thing to understand is, in LDraw, building steps indicate the ending of a step not the start. This because all models have at least one step, even if it doesn't include step commands yet. So while we only added two steps in order to separate the brick layers our house now has three building steps.

Building steps have additional options which can be used to rotate the model. This can be used to make sure the newly added parts of this step are visible to someone following the instructions. See also the "NSR" option discussed below in the editing compass chapter.

New bricks are always added to the current step, as indicated in the top left label. The building step related hotkeys are:

  • ctrl+ins, append a new step.
  • ctrl+b, edit current step options (not available for the last step because that one doesn't have a step "command")
  • pageUp, previous step.
  • pageDown, next step.
  • ctrl+pageUp, first step.
  • ctrl+pageDown, last step.

You can also navigate the steps using the toolbar building step buttons. Clicking the top left "Step 3/3" label itself will open the stepping menu containing the same actions, and some more advanced ones we don't need just now. At the bottom of the menu you'll find all steps as single items allowing you to quickly jump around.

There are numerous ways of reorganizing steps and ways to add them to existing models, these will be discussed later in this documentation. In practice it is always easier to add building steps while building the model even if they are only a rough indication you'll refine later on. Feel free to play around with step navigating for awhile, just be sure to set it to the third one before continuing.

Do note the third step is empty as we haven't added bricks to it yet. The final model will have more steps to play with.

The editing compass

Up to now I tried to familiarize you with one thing at a time using the default behavior of things only. Doing so I completely ignored the briefly discussed editing compass in the left bottom corner. The compass is arguably the most important control in LDCad, it is therefore very important you fully understand its purpose and inner workings.


You access the compass by moving your mouse over the little grid and lines in the corner. As a result it will zoom into a larger version as shown at the right. This will give you direct access to a number of often used grid/editing plane settings and displays their current state.

In the center of the compass you'll find a red, green and blue cross. These lines indicate the world/camera orientation. Red indicates left/right or width, green indicates up/down or height (notice LDraw uses a negative up indicated by the green arrow pointing down) and blue indicates forwards/backwards or depth.

Parallel to two of the three main lines you'll see the current editing plane orientation in means of a grey grid. In the corners of this grid are four icons you can use to move the camera around in one (arrow) or two (cross) directions at once.

While inside the compass you can also rotate the camera using the compass' background. Same goes for camera movement using shift or ctrl+shift. Everything will behave similar like it does inside the editing area except for zooming which will no longer use "zoom to cursor" instead it uses a plain "zoom to center".

Lets go over all the control options organized around the zoomed compass' border.

In the left top of the compass window you see the text "10 10" (while in top view). This indicates the grid stepping used with the current editing plane. It uses the Red Green Blue colors to indicate the X, Y and Z axis'. Clicking ether of the numbers will open the grid menu. The main use of that menu is selecting a different grid and or rotation stepping. This is needed if placement of bricks seem to 'skip over' the place you want it to go as a result of the grid using too large a step.

On the right top of the compass window you see the text "15 DEG" this indicates the current rotation stepping. Clicking this label will also open the grid menu. Do note both the movement and rotation steps have hotkeys set for them, it is best if you get comfortable using those instead of the menu as soon as possible as it will save a lot of time.

Below the rotation step the text "NSR" (No Step Rotation) is shown, this indicates the current "Building step rotation" state. This controls automatic camera rotations during building step navigation as we discussed in the building stepping chapter above. It is disabled by default, clicking it will enable it indicated by the text changing into "ASR" (Auto Step Rotation). A message might appear if the spin camera control is active as that limits rotational freedom as discussed below.

In the right bottom of the compass window you first see the text "TBL" this indicates the current camera system is the "Trackball" one. Clicking this label will switch to the "spin control" mode briefly spoken about above. Doing so will change the text into "SPN". Feel free to try it and see the difference with trackball mode yourself.

Changing from trackball to spin mode might cause a small jump in the camera orientation as spin control has lower freedom. It might also trigger a warning message if the step rotation feature is currently enabled, as that feature needs full rotational freedom.

After trying the spin mode for awhile feel free to leave it enabled, or switch back to trackball mode if you like to master that mode instead. You can change the camera mode at any time.

Below the camera mode the current editing pin mode is shown using a "MOV", "ROT" or "CEN" label. Clicking it will toggle trough the states. You'll probably never use this as the hotkeys are far more efficient to use.

Last in the bottom right corner it states "3D", this is the current camera projection mode also known as a "Perspective" projection. Clicking it will switch the editing view into "2D" or "Orthogonal" projection mode. Doing so will also slightly change the compass visuals, as a big cube appears. While in this mode depth will be meaningless, meaning parts way at the back of your model will be drawn at the same size as the ones at the front. While in this mode the current editing plane is also much more apparent as the camera is locked looking straight at it. You can only rotate a 2D view using the compass' cube. It indicates the 6 individual model sides (Left/Right/Top/Bottom/Front/Back). Each of those sides can also be rotated (anti)clockwise in steps of 90 degree, resulting in 24 possible different views upon your model. We don't really need the 2D mode in our little house model so switch back to 3D projection for now. 2D mode will be used in a real world example later in the documentation.

In the left bottom of the compass window you'll find the text "AEP". AEP means the camera based Automatic Editing Plane choosing feature is active. Clicking the text will disable it indicated by the text changing into "MEP" (Manual Editing Plane). While in manual mode camera rotations will no longer cause changes in the editing plane orientation. The center of the zoomed compass shows the current editing plane and you can also use it to change it. This is done by clicking the small grey/green triangles in the middle of its grid. But as with most things it is probably easier to just use the hotkeys.

Next at left bottom the text "GS" is shown, this indicates the current snapping mode. GS stands for Grid Snapping, clicking it will enable Part Snapping indicated by the text changing into "PS". While part snapping is enabled adding and moving parts will behave somewhat different but more about that below.

In the top left below the grid stepping you'll find the "ABS" label, this indicates the grid is currently absolute. Clicking it will enable a relative grid based upon the current selection. If no selection is active nothing will happen. If a relative grid is active this will be indicated by a "REL" text shown instead of the "ABS". Clicking the "REL" text will always switch back to "ABS" no matter the selection state. You'll learn more about the relative grid below.

As you can see the compass controls or indicates the state of all aspects of editing behavior discussed so far. It should be the first place to go when you need to change a setting and or want to know the state of a current one.

Basic brick placement using part snapping.

Up to now we have added new bricks to the scene exclusively using 2D grids. There is however an easier way to add bricks to a model using part snapping.

You might wonder why I wasted your time learning the grid method while part snapping is available. The main reason for this: not all LDraw parts have the additional information needed for part snapping. This means certain parts still need to be placed using the grid method. So in order to be able to use all LDraw parts you're best off leaning both methods. And by combining the two methods you are able to build models even faster, as they can be used to compliment each other.

To use part snapping you first have to enable it using the editing compass. This is done by making sure it shows "PS" as the second text in the left bottom, like discussed in the previous chapter. Personally I also disable the auto editing plane orientation ("AEP") feature when using part snapping. This because you usually want Top/Bottom mode all the time no matter the viewing angle. So make sure the compass states "MEP" and "PS" in the left bottom corner followed by putting the editing plane in Top/Bottom mode if it isn't already.

Now, using part snapping, lets add a third brick layer using the same layout as the first layer. Select any 1x4 brick and press ins (or drag one from the bin). You'll notice the new brick "sticks" to nearby bricks in a more LEGO like manner than when using grid mode. The grid is still there but it will only be shown if no "connection" was found in the immediate surroundings of the current mouse location.

Part snapping in LDCad still needs assistance by a correct or "close to" orientation especially for very symmetrical parts like bricks. So while moving around you can still rotate the new brick using the arrow keys too. Place the brick somewhere appropriate (e.g. on the left back wall). Next try to complete the layer using part snapping. The key thing to remember during part snapping is to always have an unblocked view upon the location you want to snap to, and it is usually best to build from back to front.

In situations where you are working with parts in non 90 degree orientations things can become a bit more difficult, this will be handled in the below chapter about relative grids. The house, however, is extremely rectangular so you should have no real problems using part snapping for this model from now on.

If a part doesn't "go where you want it" try rotating the camera a bit. This is possible while holding a new part in "mid air" using the right mouse button, just keep the left mouse button pressed too. It is also possible to snap multiple new parts when using ins on a multi selection (e.g. to copy the left side to the right side wall.).

Part snapping can be disabled "mid addition" or at any other time by using the shift+p hotkey if needed. This might be needed if the new part you want to add doesn't snap well due to missing snap information in its definitions. Luckily all parts used in this house model have full snap info so you won't have to worry about that for now. But if you did need a part without full info you can always fallback on the grid editing skills you learned above.

Once you completed the new layer it should look something like the first picture in the below sequence. Finish it by adding a new step (ctrl+ins) and try to complete the next two steps using the other two pictures below as a reference. Don't forget to also add steps for them after you are done.

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The white windows are a nice change of pace as we only used red bricks so far. You'll find them in "view 4" of the part bin we prepared at the start of the chapter. Just select white using the color wheel and if you have trouble finding them type "1x4x2" while your mouse cursor is inside the bin filter rectangle. This will limit the view to 5 items of which 3 are variants of the used window part. I used the first one, but it doesn't really matter in this case. Click on the right icon or press esc while the cursor is inside the text rectangle to clear the current filter and filter it on "1x6x2" to find the wider windows used in the side walls.

After completing this little exercise your house model should have six building steps of which the first five all cover a single brick layer. Before continuing onto the next layer lets first add a ground plate to the model. The only reason I didn't start with that is because it would have made the grid based editing introduction a bit more complicated. But there is no reason not to do it now. It also gives us a nice excuse to do some building step re-organizing as we need to insert a new step in front of the current first step.

Inserting a step before an existing one is very easy, just use ctrl+pageup to navigate to the first step and click the "step 1/6" label in the left top corner to open the step menu. Inside this menu click the "Insert" item. This will add a new step in front of the current one causing all the other steps to move one up. The new step 1 will be an empty one, so it will show an empty editing area as the first bricks are now in step 2.


Lets use part bin view 6 to locate a nice base plate. Base plates do have their own group but as we only need one it is just as quick to use the generic search group we prepared in view 6. Type "16x16" in the filter area to get an overview of all the 16x16 base plates. We need a plain one of which there are two seemingly identical ones. In this case this is because one of them is an "Alias part" also recognizable by the "=" in its hint as shown on the status bar. It means this particular part has multiple part numbers in the real world. You usually want the one without the "=" in its description as that is considered cleaner modelling while using LDraw.


You can exclude these special alias parts by using the advanced part bin filtering dialog. This is handy if you don't plan to use them ever. You open that by clicking the filter text area or by pressing F03 while the mouse is inside the part bin window. This opens the dialog shown in the picture at the left. Use it to uncheck the "Alias parts" item at the right. Many people also want to exclude "Colored parts" which are parts with a unchangeable color, so feel free to uncheck that too.

When done adjusting the settings you need to apply them to all the other bins and make it the default or it will only be used for this part bin group until you navigate its view away from it or when you restart LDCad. You make it the default by clicking the "Options" button which opens a popup menu. In that menu click "Apply to all and set as default" to make it permanent. Next you can close the dialog by clicking "Accept".

Lets resume adding the 16x16 base plate. Drag it into the empty editing area and because there is nothing to snap to just place it anywhere in the center for the moment. Next navigate to building step 2 making the first brick layer visible again.

The base plate is now visible but at the wrong place, unless you are very lucky or are cheating using the coordinate panel. Luckily you can move any part no matter the step they reside in. Grab the base plate so it is "disconnected" again, this time it will snap to the bottom of the first layer. Position it so the left, right and back sides extend 2 studs past the bricks. Having done this go back to the last building step (now at 7) using ctrl+pageDown, which should look something like the picture at the right.

At this point I think you are probably familiar enough with the basics of editing to finish the rest of the house by matching the below building step screenshots. Don't forget to add a new step before starting the next picture. When finished you should have 17 steps (you don't have to add a step after placing the final part).

If for any reason you did forgot a step or added parts to the wrong one, don't worry about it you can correct it later as explained in the below "Basic building step management" chapter.

The only pitfall in these pictures might be the door and its frame parts, as we didn't prepare a part bin view for those. You could use the unused view 5 to navigate to bodywork/doors or redirect view 4 (windows) to it by going one level up and then side step into doors. Once inside the door group filter it on "1x4x6" and you should have no trouble finding the needed parts. Just be sure to select the frame variant with the small holes at the left. You could also use view 6 to filter on "1x4x6" but it will list more then just door related parts.

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Basic building step management.

Now there are 17 building steps it is more rewarding to navigate trough them using the pageUp and pageDown hotkeys as you can hold them down to make a little animation. But as this is your very first model it is likely you messed one or two steps up a bit. These mistakes can be corrected in multiple ways though. The main one is using the step menu you can open by clicking the "Step 17/17' label in the corner.

We already handled inserting a step so if you missed one navigate to the one that should be next and use the "insert" item from the menu. If you missed multiple steps it is best to add them for lower steps first as this fixes higher step numbers as you go. After inserting the new step navigate to the first step the bricks we want to move are currently visible in. This way the should be easier to select using ctrl. Once they are all selected you can move them to the correct step by using the "Move to step" submenu in the step menu. If you, for example, forgot step 9 and have all bricks that should be in that step selected just click the "Step 9" item in the "Move to step" menu and it will be corrected. You can do this for any brick currently in the wrong step.

An alternative to the above could be using the "Selection insert" item, this will insert a new step separation before the currently selected part. This is handy when you know you added parts in the correct order, but just forgot to add the step itself. In this case you can select the first part of this forgotten step and click the "Selection insert" item. It will split the current step in such a way the selected part becomes the first part in the original step. All the bricks in front of it will be moved into a newly inserted step.

You might also have added a step twice while not noticing it until some new bricks were placed. This can be fixed by navigating to the empty step, followed by clicking "Delete" this will merge the current step with the next one essentially removing it.

The above methods can also be used to add stepping to an existing model whom currently has none. But this can be very work intensive as selecting all parts in a certain step can be very tedious due to lack of access etc. In such cases you most likely want to master the "Source window" as explored in another section of the documentation.

Building at angles.

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The, now finished, house model is very rectangular, this is not so strange as most LEGO models are. This is not the case for all models though, so it is also possible to build on any angle while using LDCad. To do this a number of tools are in place to help you doing so.

To illustrate the main problem lets add something at an angle to the house model. Maybe a small tree or something. While (still) using part snapping build the trunk as shown in the picture at the left. Next disable part snapping for a bit as this makes the problem we are dealing with easier to explain. Do this using the compass or the shift+p hotkey.

Now while using all your grid editing skills try to finish the tree like shown in the picture at the right using one 1x3 and three 1x1 bricks. Even though new bricks uses the same orientation as the plate (if added last) parts still will not go to the edges of the plate as those places are "off grid". You could disable the grid stepping or set it to a very fine one to get close to it. But it will be very unlikely to be precise, if done by eyeballing alone.

The main problem here is the plate is "crooked" in relation to the grid. This because the grid dictates what's left/right, up/down, and front/back in the editing world. To add stuff to the plate we would need different rules for those directions. You might realize that using part snapping will fix the angle problem in this case (but only if you you clicked the diagonal plate last). Because the snapping feature jumps parts to the awkward non grid positions for you. Although this works in this case it will not come to the rescue in all cases, not even when excluding parts with incomplete snap info.

The correct overall way of doing this sort of angular building is by using either a submodel (handled elsewhere) or using a relative grid. Let's explore using the relative grid method. It is enabled simply by pressing the "ABS" text in the compass while the green plate is selected. The text will change into "REL" indicating the grid is now relative. You can also use the "o" (Origin) hotkey.


Once the grid is relative its color in the compass will change to orange (as shown in the picture at the right). The compass will also show two sets of world axis. Of those the thicker ones are the relative ones and the thinner are the original absolute ones. You can disable the absolute ones in the "prefs/editing" menu if it bothers you.

In the new grid state it's suddenly easy again to add a brick to any of the plate's studs. This because now the "world" is rectangular again, it just is so in relation to the green plate. Try completing the tree as shown in the picture at the left.

Once you're done building at this particular angle press the "REL" text in the compass or use the o hotkey while nothing is selected.

What's next

The above is all you should need to get started modelling with LDCad. As with most things it will need practice to get really going. One way to get some practice is by digging up some old LEGO instruction booklets (or get some from the net) in order to try recreate the models digitally. For beginners it is usually best to use small "Town" or "Creative" sets for this at first.

Once you are comfortable with the basics of editing feel free to continue on to the next page: Advanced editing, in which we will be exploring submodels, bendable parts, and more.