Troubleshooting

Can't Select a Part

I can't select a part. It's displaying in red.

You've selected a solid. You can assign only a surface as part.

From the solid, you can create a surface using the Surface Extract tool.

Now you can select the surface when assigning the part.

I can't select more than one part. When I try selecting more parts, only the last selection is used.

You cannot select multiple disconnected parts. You need to combine them.

Use the Combine tool to combine multiple disconnected parts into one connected part.

Now you can select the combined part when assigning the part.