Project Cut Edges Sculpt Cylinder not a circle

[davoque]

I created a simple cylinder using sculpt and finished the sculpting, then placed a construction plane half way up, started a sketch on the plane and projected the cut edges of the cylinder onto the sketch, expecting a perfect circle.

However, though it looks like a perfect cirle, it isn't and trying to use sketch contraints like tangent, don't work.

[deyop]

Solid and Patch models are based on a different type of geometry than Sculpt.  The method of defining a cylinder in solids is precise.  For any point on a cylinder there is an exact offset distance from the center.  Sculpt geometry is based on NURBS surfaces and although close, they are not precise like solid and patch.  The advantage of the sculpt geomtery is the abilty to edit it easily.  We could do a better job of distinguishing the results of project so you wouldn't be surprised.

If a precise intersection with the plane is important choose the solid or patch geometry.  That being said you can constrain other geometry such as splines to the project from the sculpt entity however I couldn't manage the tangency with a closed circle as you may have tried.

[davoque]

Thanks for the quick response.

I need the flexibility of being able to edit the sculpt and have other geometry follow it.

I figured out a work around to get a tangent, by drawing a construction line out from the centre through out past the egde, then drawing another construction line perpendicular to that but not connected, then take the end of the second line and apply a coincident constraint to the first line and the "circle".