Re: trim projection.

When trimming curves to other curves, the view you use can make a difference if the curves don't intersect and need to be projected to intersect. The construction plane of the view will get used for that projection.

But trimming a surface or solid to a curve is not view dependent in MoI - you will get the same results for this no matter which viewport you use, which is a little different than Rhino.

The process works like this - the first thing that is checked is if the curve is actually already on top of the surface or solid - if it is then it will not be projected. I guess this might be good to change since it can inhibit the projection of a planar curve through to the other side of the object.

Anyway, the next test is if the curve is planar. If it is then it will be projected along its plane normal.

If it is not planar, then it will get sucked down on to the surface by finding the closest point on the surface for every point on the curve ("pullback" method in Rhino).

So the view used actually doesn't have any influence on curve-to-surface projection.

If you want explicit control over the projection direction, you can just extrude your curve along the desired direction and use the extrusion for the cutting object in the trim.

- Michael