[KenH]

Hello Paul,

I am not sure how you are modelling the mouse, but presumably you are generating a mesh. You mention adding vertices. These should be added using the <vertex - insert vertex> command (vertex mode, control-shift I) between two existing vertices on your mesh. This will add a vertex between the two you originally selected, and will be part of the object.

Then use the "move toward" plug-in, and do not attempt to move the vertex by hand. In that way you can "slide" the new vertex towards one of the previously selected vertices and it will follow the edge of the existing face between those two vertices, thus maintaining the shape. You can then add a line (vertex mode control-shift-L) between your new vertex and any other within the boundary of the same surface to divide it into smaller surfaces.

Then when you have your mouse button outlined, select its surface and use the "extrude by normal" function.

I am sorry if I have misunderstood and you already are familiar with this. For me the "move toward" plug-in is the key for most operations in AC3D to maintain accuracy where your objects or faces do not align with the principle x, y, and z axes.

Regards
Ken