topic Re: Changing the surface of tangency when lofting edges together in Fusion API and Scripts Forum

Changing the surface of tangency when lofting edges together

gnm4pm — Mon, 22 Jul 2024 18:32:51 GMT

TLDR: Is there a way to flip tangency direction when lofting paths together using the API.

I am currently writing a script that lofts two faces together, and has both end conditions set to be tangent. This essentially requires me to strip the faces down to the collection of edges and create paths in which I loft to and from. I have run into the problem on multiple occasions where the tangency direction is flipped from what I would like it to be. I have looked around for flipping the tangency direction throughout the documentation to no avail. I have some solutions that I am implementing right now although it is not optimal. The one solutions requires me to delete the surface faces, create the loft, and then delete the delete using the .deleteMe() feature. This causes the lofts to be created but lose their references and in the timeline appear yellow. The second solution is to find the faces that the contain the same edges but are the tangency direction that I want it to be. This however requires me to sort through multiple faces, find the one edge per face that I want included, and then create paths using those edges. This solution is also not necessarily scalable in my process as referencing each face for the singular edge that will consistently change properties making it difficult maintain accuracy. Is there any way to possibly do this? Thanks for your help.

Re: Changing the surface of tangency when lofting edges together

BrianEkins — Mon, 22 Jul 2024 19:12:26 GMT

If I understand your problem, I think all you need to do is to set a negative tangency weight value. That will reverse the direction of tangency.

Re: Changing the surface of tangency when lofting edges together

gnm4pm — Mon, 22 Jul 2024 19:24:00 GMT

According to the documentation .setTangentEndCondition(valueInput) requires the valueInput to be a positive value between 0 and 1.

Re: Changing the surface of tangency when lofting edges together

Jorge_Jaramillo — Mon, 22 Jul 2024 21:41:05 GMT

Can you share an image of your design to understand it better?

Re: Changing the surface of tangency when lofting edges together

BrianEkins — Tue, 23 Jul 2024 06:10:00 GMT

The documentation is wrong and needs to be fixed. I just tried it with a value of -1, and it reversed the tangent direction.

Re: Changing the surface of tangency when lofting edges together

gnm4pm — Tue, 23 Jul 2024 13:30:31 GMT

Interesting. I just set up a sample script myself to loft two cylinders together, and changing the value negative did alter the tangency. One thing I noticed however, is that if you make a body with both tangencies positive, and then a second body with both tangencies negative, that the bodies are not opposites of each other in terms of tangency direction. Essentially tangency direction, which is what I want to change, does not equate to a positive or negative tangency weight. When changing the weight, the loft is still considered tangent to the same face just coming from a different angle, where I want to change the face that the loft is tangent to. I am attaching some images to better illustrate my point. By changing both tangency weights to be equal at negative or positive 1, I get 2 loft shapes, by changing the directions to be the same between both at negative and positive tangency I get another 2 loft shapes. There are many more combinations then what I am showing but this is the least amount that explains my point.

Ultimately, changing the tangency to negative does work, but it doesn't achieve the shape that I want. The only way to do that is to change the tangency direction which I am not sure can be accessed through the API.

Also I will attach the final image in another reply since 3 is the maximum attachments allowed.

Re: Changing the surface of tangency when lofting edges together

gnm4pm — Tue, 23 Jul 2024 13:26:04 GMT

Re: Changing the surface of tangency when lofting edges together

gnm4pm — Tue, 23 Jul 2024 13:27:41 GMT

I just shared images that better explain my problem in a reply to another post below. Thank you.