Offset Spline Distance

famadorian

I've drawn a spline and I'm creating an offset, but when dragging a bit too far, the offset spline just disappears and that's one of the error messages. 

It acts as if there is some limit it can offset from?

NeilCooke

Offset too far and the spline will self-intersect

famadorian

NeilCooke said:

Offset too far and the spline will self-intersect

ok, but does it self intersect the spline I've drawn here (red pen)?: The reason I ask is because it won't go any further than what's shown in here (blue spline):

NeilCooke

Not sure what you mean? The original spline has two convex regions whose curvature is smaller than the value you want to offset by. 

famadorian

I'm not sure I understand. Because it has convex regions that will end up going into eachother, that's normal for an offset operation, is it not? What if this is a road? Can we not build a road here because we have two convex regions whose curvature is smaller than the value we want to offset by?

NeilCooke

Sorry, I meant to say concave. Your image with offsets has no intersecting regions, but if you offset some more, here is where the problem would be:


Splines in a 2D parametric sketch solver are somewhat different than what you can do with a truckload of tarmac

I would suggest splitting the spline where the areas of high curvature are, offset them, then manually trim them afterward. That will give you sharp vertices that you can fillet if you want.

famadorian

Are you saying we can't do something like this in Onshape?:

NeilCooke

Correct - please submit an improvement request to add this capability.