Draft Angle?Ahhhh!

Hi - I need to a 20 degree draft to a model which is being used to create a die. Keep thinking this should be something which Rhino can easily do - however at the moment I’m going round in circles and feel like I’m missing something???

I’ve ended up extruding curves tapered at my required angle - however this seems like a backward way to achieve this as I then have to carry out several blends, sweep 2 rails, etc, in order to adjust corners??? I have several other models which require a draft angle to be added and can’t afford the time spent on each which has been spent on the first model.

Any help is much appreciated!!!


Hi Fiona- it is not that easy in Rhino. Try the TestSilhouette command, (No pre-selection, so you can see the command line settings) with the view set looking from the pull direction, and set Draft to 20. Then use the Fin command with Direction=Tangent on the resulting curves - that should get you some basic draft surfaces… no doubt some cleanup will be in store.


Can you not use the DraftAngleAnalysis?

I usually set the top value to the desired value and then remove one degree for the lower value.
That way everything blue is ok and everything else is not.
(Set the mesh value manually to make sure the analysis mesh is within tolerance for you.)

Adding a 20 degree draft to a model is basically rebuilding it, it’s not easy at all.

You wonder if the “taper” transform or a cage might save some of it. It might not be accurate, and the latter likely won’t, but it might be worth a test.

Is 20 degrees a typo? I usually use 1 or 2 degrees (for injection molding) depending on the material.