[WML-Source: Special.wml][TOC][Part00]

[chapter]Special Modeling Techniques


Dupliverts are an easy way to make arrangements of objects. In fact on every vertex of a mesh an instance of the base object is placed. The placed object can be of any object type which Blender supports.

Load the scene "Dupliverts00.blend" . It contains a simple scene and a column. Switch to Layer 2 and create in the top-view (PAD_7 ) a mesh-circle with 12 vertices.


This circle will be our base for the arrangement. Now switch Layer 3 on with SHIFT-3KEY . The column appears in the middle of the circle. Select the column and then add the circle to the selection (hold SHIFT while selecting) and press CTRL-P to make the circle parent to the column.


Now select only the circle, switch the ButtonsWindow to the AnimButtons F7 and select here the option "DupliVerts".


Note that the base column is still shown in the 3D-views, but it is not rendered. You now can select the column, change (scale, rotate, EditMode) it and all dupliverted objects will show up the change. But the more interesting thing to note is that you also can change the parent object.

Select the circle and scale it. You can see that the columns are uniformly scaled with the circle. Now enter the EditMode TAB for the circle, select all vertices AKEY and scale about three times bigger. Leave EditMode and the dupliverted objects will update. This time they still have their own size but the distance between them is bigger. Not only can we scale in EditMode, but we can also delete or add vertices to change the arrangement of columns.


Try to delete the left four vertices of the circle in EditMode. Select the two on the left and extrude them to the left. Repeat this step a few times and then leave EditMode. We now have an arrangement of columns similar to those which can be found in a temple or a big hall.

[subsection]Rotating dupliverted objects

With the "Rot" option in the duplivert section of the AnimButtons, you can rotate the dupliverted objects according to the face-normals of the parent object.


Add an Icosphere with two subdivisions. Next, add a cone and size it to a spike on your club.
The standard "cone"-primitive of Blender will render with a seam on the side when it is drawn smoothed. Often a cylinder, with all of its vertices on one side scaled to one point, is the better choice


Now, make the icosphere the parent of the spike. Select the icosphere alone and make it "Duplivert" in the AnimButtons. Note the effect of the option "Rot" when you click on it now.


Depending on the orientation of the spike relative to the world, you may now need to rotate the vertices of the spike in EditMode to make all the spikes point outwards.

Again, the base mesh is not rendered.


The method of "Dupliframes" can be described as modeling with animation. Here are two illustrations of the technique.

[subsection]Arrangements of dupliframed objects


This method is similar to the dupliverts method, but this time we can use curves and animation paths to arrange our objects.

For a roller coaster animation, you start with a curve describing your tracks. A simple bevel will do your tracks ( "Rollercoaster00.blend" ), the curves are also reused for the camera path.

Add a cube that will act as sleeper for the track. Scale it so that it fits to the tracks. Now, select the sleeper, then extend the selection by the object "SleeperCurve" and make the Curve (with CTRL-P ) the parent of the sleeper.


Select the object "SleeperCurve" alone and activate the options "CurvePath" and "CurveFollow" in the AnimButtons F7 . It maybe that the sleeper is now dislocated, in which case select the curve, then extend by the sleeper and press ALT-O to clear the origin. Then position the sleeper down under the tracks. Until now we have done little more than animate the sleeper along the curve. This can be verified by playing the animation with ALT-A .

Now, select the sleeper and go to the AnimButtons F7 . Here, activate the option "DupliFrames". With the "DupSta:" and "DupEnd" NumButtons you can define the start and end of the duplication.


If the sleepers are too close to each other, you can adjust the number of objects using the "PathLen:" option of the sleeper-curve.

[subsection]Modeling with dupliframes


With Dupliverts, not only can we create separate objects but we can also create one big object. Ideal for that purpose are NURBS-surfaces, because we can change the resolution easily after creation, and if we need to we can convert them to a mesh object. Also, the surface objects from Blender are ideal for "skinning".


Create a surface circle (ADD->Surface->Circle) in a front view. Don't leave EditMode, just move the vertices of the circle until they are about 4 times the size of the circle diameter to the left.


Switch to a TopView and insert a key using IKEY , then choose "Rotation" from the pop-up. Advance the frame slider by 30 frames (three times CURSOR-UP ). Now, rotate the circle 90 degrees and insert another keyframe.


Use F7 to open the AnimButtons and activate "DupliFrames". You can now see an arrangement of circles in your TopView. In the shaded 3DWindow you will see nothing so far, this we'll change at the end.


Switch one window to an IpoWindow using SHIFT-F6 , and select the "RotZ" curve. Now, change the Ipo to "Extend Mode Extrapolation" .

Switch off the "DupliFrames" option in the AnimButtons, and insert a keyframeanimation for the size of the circle. After that, animate the location of the circle with a keyframe animation along the z-axis. Here you should also use the "Extend Mode Extrapolation" in the IpoWindow. You will get something that which is shown in the next picture after you have activated the "DupliFrames" option again.


[point]Making it real

To turn the structure into a real NURBS-object, select the base object and press CTRL-SHIFT-A . A pop-up menu will appear prompting "OK? Make Dupli's Real".

We now have a collection of NURBS forming the outline of our object, but so far they are not skinned, so we cannot see them in a shaded preview or in a rendering. To achieve this, we need to join all the rings to one object. Without deselecting any rings, press CTRL-J and confirm the pop-up menu request. Now, enter EditMode for the newly created object and press AKEY to select all vertices. Now we are ready to skin our object. Press FKEY and Blender will automatically generate the solid object.

When you leave EditMode, you can now see the object in a shaded view. But it is very dark. To correct this, enter EditMode and select all vertices, then press WKEY . Choose "Switch Direction" from the menu and leave EditMode. The object will now be drawn correctly.

The object we have created is a NURBS object. This means that you can still edit it. Even more interestingly, you can also control the resolution of the NURBS object via the EditButtons.


Here you can set the resolution of the object using "ResolU" and "ResolV", so you can adjust it for working with the object in a low resolution, and then set it to a high resolution for your final render.
NURBS objects are also very small in filesize for saved scenes. Compare the size of a NURBS scene with the same scene in which all NURBS are converted (ALT-C ) to meshes.

[section]Modeling with Lattice


A Lattice consists of a three-dimensional grid of vertices. If the vertices are moved from their regular positions, this will cause a deformation of the child objects. Lattices only affect Meshes, Surfaces and Particles, and they can be used to give them a 'NURBS-like' flexibility. A Lattice does not affect the texture coordinates of a Mesh Surface. Subtle changes to mesh objects are easily facilitated in this way, and do not change the mesh itself.

A Lattice always begins as a 2 x 2 x 2 grid of vertices. Use the EditButtons->U,V,W settings to specify the desired resolution, then the Lattice can be deformed in EditMode. If there is a Child Object, the deformation is continually displayed and modified. Changing the U,V,W values of a Lattice returns it to a uniform starting position.

Lattices can be used as a modelling tool. They also allow you to make the deformation permanent. Use the SHIFT-CTRL+A command. A menu will ask: "Apply Lattice deform?".

-cw- Last modified: Wed Nov 1 14:45:40 CET 2000