The collide tool is probably one of the most versatile tools used in Pixels and can make modeling much easier. From eyelashes to labels, we'll go over the basics to get you started working with, and understanding how this tool works.

This tutorial requires:

Pixels3D | studio | v3.6 and above

The Collide tool is helpful for us in creating many shapes with ease. By selecting two different shapes, we can collide the CVs from one object to the next, as shown on the right.

How the tool works is, first select the surface you wish to collide to, then shift-select the object you want to collide onto the first object. Then choose Reshape>Collide and the tool will perform our collision test.

Lets examine the image above to understand how and where CVs collide. Set the views to show Normals. Open View Options, click the Drawing Options button, and check the Normals checkbox. Normals show the vector in which a point travels in 3D space.

Notice the sphere's faces are pointing away from the center of the object. This means the CV's vectors will collide with anything outside the spheres mass. If we were to create a mesh and move it on the z axis, past the range of the spheres circumference, some of the CVs will collide with the surface of the mesh. After colliding the sphere's face smooshes to the surface creating the shape pictured top right.

Select Shape>Spline and create half the shape of our small glass like pictured on the right.

Then choose Shapes>Lathe and hit return. The spline has been rotated on the Y axis creating our full 3d glass as pictured.

To get more detail in our collision lets increase the subdivision of the Lathe object to 4u and 4v.

Now we'll create a shape to smoosh the sides of our glass. Choose Shapes>Mesh and click OK.

Open Object Info ( cmd-i ) and set the X Rotation of the mesh to 90.00. Move the Mesh on the z as shown, Scale it up, and Park it ( Control>Park ).

Before we start colliding, notice how the mesh is inside the actual Lathe shape. This means we need to change the CVs vectors to point to the center instead of away, select the Lathe shape and choose Reshape>Invert invert the normals.

Now lets collide our Lathe shape to the mesh. First we need to control which CVs we want to collide and ones to not collide to remove unwanted collisions. Enable Tag Mode, and the Z Axis Constraint. By Tagging CVs, and selecting an axis, we can selectively collide CVs on the axes of our choice.

To make selecting easier, open a schematic view in the right view pane ( open View Info and select schematic in the dialogs menu ) cmd-click on the Lathe shape, then cmd-drag a rectangular selection over the CVs past the mesh as shown. Finally, cmd-click the Mesh, then shift-cmd-click on the Lathe and perform a normal collision ( Reshape>Collide ).

You should see something very similar to the image on the right.

Now lets step this 8 times for a full rotation. Select again the Lathe only and in Object Info rotate it 45 degrees on the Y Axis, and repeat the step above.

After stepping the above process until you've come full circle, you should see something similar to the image on the right.

Hopefully this tutorial has given you a clearer understanding of the collision tool, and should eliminate the frustration of wondering why it works the way it does. Take care.