> Michael when you get a moment (LOL) would you demo the best way
> to use the project to curve features. I have my own work around but
> I would like to know how it was designed to function.

Basically it is a way to create a curve that is following along the shape of a surface, so that you can use that curve for further constructions.

The most simple function is that you take a planar curve, select it, run Construct / Curve / Project, then select the surface you want to project on to. By default it will project perpendicular to the plane of the curve, but you can also pick 2 points to define a different projection direction if you want, before pushing "Done" to finish the project command.

Here is a mini tutorial to show what kind of situation you might use this for.

Say we want to create this shape, a sphere with grooves cut in it:



The base sphere shape is simple, just draw it with Draw solid / Sphere. But to do the grooves, we're going to have to construct some shape that follows along the surface of the sphere.

After drawing the sphere, I went to the Front view, and drew some curves using Draw curve / Freeform / Control points, that looked like this:



Now we can project these curves on to the surface of the sphere. Select these 2d flat curves that were drawn in the front view, and run Construct / Curve / Project, then select the sphere as the projection target and push Done. After deleting the original 2D curves, you are now left with these curves that follow the surface of the sphere:



Now these curves can be used for constructing the grooves by sweeping. To do the sweeps, I drew a little circle off to the side. When sweeping, if the sweep profile curve is away from the curve MoI will automatically move and rotate it in place, so it is often quick to draw the sweep profile off to the side and let MoI do the work of moving it into place rather than needing to place it yourself.

Then I did 5 sweeps, for each one selecting the little circle, then running Sweep (you can use Right-click to repeat the last command also), then selecting one of those projected curves as the rail path curve.



Now you can select the sphere and use Construct / Boolean / Difference to slice away the sweeps to create the final grooved sphere result.


So basically when you want to construct something that kind of hugs along a surface, that's when you may want to use Project to set up the curves.

One quick note - it is not necessary to project first before trimming a hole, there is an automatic projection built into Trim already.

Hope this helps!

- Michael