Shake those params.

'Primitives' are the basic building blocks of 3D: cubes, spheres, a plane, cylinders. The 3D Assistants shape your 3D layers with these primitive shapes. This page explains some of the useful parameters that are common to many 3D Assistants palettes.

The Distribution option.

The 'Size' or 'Dimensions' options set the size of the bounding box. For Distribution tools, this is the size of the bounding box that contains the primitive that the layers will be distributed in. For the Creator tools, it's the bounding box that the layers will be placed around.

For Box Creator and Cubic Distribution, this is exactly the size of the cube that's created. For the other tools (like Spheriod), this will set up a rectilinear boundary. The actual distribution space will vary according to the primitive shape.

Starting Value option.

For both Distribution and Creator tools, the 'Starting Value' is the starting point of your 3D structure. For Distribution tools, this is the point in 3D space where the Assistant will begin distributing your layers. For Creator tools, this is the center of the primitive you’re creating.

By default, the first layer will be distributed or created at the upper left corner (0,0,0) of your composition. Of course, you can move this starting point to anywhere along the X, Y, and Z axes, positive or negative.

Repeat Layers option.

'Repeat Layers' is very useful if you’re trying to quickly fill an area up with layers. This option will duplicate your selected layers however many times you tell it to.

For example, you are creating a sphere with Spheriod Creator and have 7 layers in your comp. Those 7 layers aren't enough to create the sphere, but you're not sure how many more you need.

Set 'Repeat' to 10, and the Assistant will duplicate layers until the dimensions are met. If you need 48 layers to create the sphere, the Assistant will create an extra 41 layers, then stop.

Distance/Increment options.

The 'Distance/Increment' settings are used to determine how far apart layers will be distributed. Keep the 'Min' and 'Max' settings the same for uniform spaces between the layers.

Setting different values to 'Min' and 'Max' will result in a random distance between these two numbers to be selected for each layer. The 'Increment value can create increasing or decreasing distances between layers.

Insert Keyframes option.

The checkboxes in the 'Insert Keys' section allow you to specify which properties will have a keyframe set for them.

This is a convenient way of setting the appropriate keyframes if you want to eventually animate your layers. You can certainly do this from the main AE interface, but this is a bit more convenient and makes sure you set keyframes for all the necessary properties.