Should curves used for solids and surfaces see differences at corners at high mag?


If I make surfaces from a set of curves, coming together at a corner, then extrude surfaces to make solids, if I then zoom in a lot on the corner, should they not all be together or should I see mismatching different lines ?
I see the original line set, then another set for the surface, and for the solid and another image offset again for the solid.

If I snap a line from the corner at normal mag, then find I get a boolean fail or something, I zoom in to see if there are any visible gaps and see three sets of lines, so then wonder just which set should by line have snapped to !

in example just which corner should I put my red arc to before making a surface from it I wonder.

These mismatching corners confuse the $£%*& off me when trying to stay pure and precise to avoid failures.

Seeing double at corners.3dm (175.3 KB)


Hi Steve - If I delete your object and extrude the curves myself I do not get this discrepancy … the render mesh is a little off at that zoom but the wireframe is not.

Seeing double at corners_PG.3dm (51.8 KB)


Well there actually is a mismatch of 0.0004219 mm at that corner between the red and turquoise wireframes… However, the slight displacement you see between the solid edges and the mesh display that allows you to see it as a surface is pretty normal at that magnification. it’s a function of how both curves and display meshes are calculated and sent to the screen.


If my Rhino creates such mismatch, and yours Pascal doesnt, can you see my frustration.

Why is that ?

Mitch are you saying yours does ?

I find it hell to work with, my failures which I do fix are due to me drawing lines to the wrong bit of a corner etc.

I use snap then find it is not where It should be. It gets very crazy with seeing double of triple at junctions.

Maybe we should have a zoom limit such that it doesnt enable vision beyond what is in tolerance ?

I find that despite drawing lines along a datum, in time I zoom right in and see three or four, and wonder why they are not all together. They were snapped to datum, drawn horiz etc.


Could this be solved by using a 1.00 / maximum render mesh on all surfaces? I will do that if I’m getting ‘jaggies’ / trouble selecting / need a high quality render.