Inconsistent draft operation

Hi, noob here… I’m having trouble creating my desired draft angle for items extruded from splines. I can do the extrusion just fine whatever the shape, but the draft angles it lets me choose seem to vary from one item to the next. I can always create a draft angle that starts with the outline shape and gets bigger, but not the other way, where I’m trying to angle it down to a V-shape, say. Sometimes I can make the angle 5 or 10 degrees, but no more, sometimes it excludes lower angles but lets me create higher draft angles. It’s somewhat random and seems to vary depending on the size of the object. In other words, if I make the item larger in X-Y but keep the same extruded distance, I can give it a larger draft angle. I don’t see the problem for simple shapes like rectangles and circles; I can give those any draft angle I want.

Any ideas?

Edit: It behaves the same on MacOS and iOS.


The inward draft possibly fails because the geometry would be self-intersecting over a certain angle. This can happen mainly along tightly curved sections.

If you have some time, just give it a try: as you make the curvature of the spline bigger, the allowed draft angle will also increase (or decrease if it is negative)

Thanks, Peter. Yes, that’s exactly the behavior I’m seeing. I appreciate the explanation.


Im having draft issues too

I make parts to use as sand cast patterns.

I have lettering i print to use on them
But i need to put 5degree draft on them and most of the time it wont let me.

Like for example i have lettering with two capital B’s in it.

It will let me put 5degrees of draft on it and extrude it .125"
Works perfect
Then i goto the second B and it wont let me it says the draft isn’t doable

Even tho i just did it to the same letter in the previous operation
Same size, everything

Ive even tried making them way bigger, do draft and then resize

Doesn’t make any sense to me.
Id really like ot to work!