Draft Angle Analysis


I am trying to use the Draft Angle Analysis tool in order to create a parting line of a SubD object for mold making, however, sometimes the draft curve that is generated is not continuous and has a lot of gaps. How do people get a perfect continuous curve around the model using this tool? Additionally, I have seen videos where the Draft Angle Analysis tool could be adjusted to fit a model better (avoiding undercuts), but I do not know how that is done. Any advice will help. Thanks.

Hi Will - please post an example object and pull direction.


Ah, sorry, a Rhino file would be best. If you cannot post here, please send to tech@mcneel.com with a link back here in your comments.


answered via support bee/ tech support.

Hi all,

I am a new member here.
I am facing the same issue here with the subD model wont generate a parting line through the draft analysis. Is this only possible with solid models?


Hi Babis - this seems to work here in my quick test-


Can you post or send to tech@mcneel.com (with a link back to this topic in your comments) an example where it fails?


Hi Pascal,

I’ve just sent an email to tech@mcneel.com and shared the model for your review.

I wanted to share this with the community, as others might encounter a similar issue.

I’m working with a complex physical form model (head). After converting from mesh to SubD and executing the ‘DraftAngleAnalysis’ command to create a mid Draft curve, I’m not getting any result, regardless of the processing time. I suspect it might be due to the extensive number of faces, but being a novice, this is just an assumption.

Here’s the process I followed to achieve a seamless parting line. Please note that these are my initial steps in Rhino, and there may be more efficient methods:

  1. I translated the object into a solid. Despite repeating the process, it generated a parting line quickly, but tweaking the options didn’t yield a continuous parting line.
  2. I discovered that I could join it using the ‘Join’ command, creating a uniform curve.
  3. I then rebuilt the parting line, resulting in a nice continuous parting line on a solid object.

Feel free to check the model, and any insights would be greatly appreciated. Thanks!

Hi Babis - this seems to be bogging down on finding the silhouettes.