Drawing Rules and Examples

In order to achieve the desired 3D model, one must follow certain rulees about drawing in 2D. Below we summarize how the extrusion process works.

What AutoCAD Entities Can Be Used

Circles - used primarily for round pads and for round holes in a ground plane. Can also represent solder balls when so specified. Circles can also be used as vias.

polylines with width - these represent circuit traces or wires depending on how the layer that they lie on is defined. A polyline width may not be closed and should not fold back on itself. Example

zero width closed polylines - these generally represent conductor regions or substrates depending on the layer definition. They should not fold on themselves and may not be assigned a width. There are two distinct methods of building areas from these polylines - Regular and Reversal. As a user you can specify layer by layer which method to use.

blocks - blocks can be used but they will be exploded and the flattened results inside the block are what will be rendered in 3D. Note that when a block is exploded, data belongs to the layer that it was drawn on - not the layer the block was inserted on.

What Entities are Ignored

lines and arcs - line and arc entities is ignored. However a utility is provided that can link lines into closed zero width polylines.

text - text entities are ignored. However several utilities are included that can use text to label pins and nets.

hatch - hatches and regions are ignored.

The Importance of Layers

Layers are important. Every item on a given layer will have the same thickness in 3D and lives on the same level. So things need to be organized by layer.

layer names - you are free to use any layer names you wish ... but we recommend that 1) you use names that describe the function of the layer and 2) don't use spaces in names or special characters.

layer order - the order in which you create layers or AutoCAD shows them is immaterial. During the extrusion process you will define the layer order stackup.