@Lowell Any updates on V6 being able to create developable surfaces? Making DevSrf available with the current functionality would be much better than nothing.
Previous question on this topic DevSrf for Rhino 6
Status is still the same. No new info.
Hi Lowell, is the status still as it was in 2016 ? Thanks , Mark
@markintheozarks - There’s a new command in the V6 WIP, DevLoft, that is moving toward some of that functionality.
I wasn’t quite ready to announce it since it’s still got some rough edges and hasn’t been tested very much except internally.
However, it is there and I’ll be working on it more now.
Lowell
@Lowell Good news that a new command for developable surfaces is being worked on, though I’d be satisfied with DevSrf ported to V6…
However, the current version of DevLoft has a significant problem. It appears to force the surface to span the entire length of both rail curves, even when there is not a developable surface which spans he entire length of both rail curves. Here’s an example using the simplest developable surface, a section of a circular cylinder. DevLoftTest_DC001.3dm (98.2 KB) The rails are circular arcs which lie in parallel planes and on the same circular cylinder.
The exact solution for a developable surface between the rails is a section of a circular cylinder.
However DevLoft (in (6.0.17290.10121, 10/17/2017) creates a surface which significantly deviates from the developable surface.
DevSrf in V5 gives the correct solution.
We may get to porting DevSrf eventually.
The main feedback I’ve gotten about it is that it’s too complicated.
Understand about users considering DevSrf too complicated. But DevLoft needs fixing before official release.
A related buglet - https://mcneel.myjetbrains.com/youtrack/issue/RH-42204
-Pascal
Is Devloft now oke?
and will devsrf be available for r6 or is it there already because I can’t find it
sorry
edward
Hello Lowell,
Thank you for your amazing work I have a question about devsrf, which I was wondering if you wouldn’t mind.I am a teacher and I like to try to understand tools the tools that I am using so that I can give basic explanations to students. Is there an academic paper that you could point to me to understand the algorithm or mathematical theory behind devSrf. I am not trying to understand the implementation, just which of the many theories regarding developable surfaces it is built around. I understand if you can’t want to share, but I just thought I would ask. Thank you for your help.
Best,
Carl
@cdapolitodworkin I’m not associated with McNeel, but I have studied developable surfaces and have used DevSrf and DevLoft.
A developable surface can be considered as a set of ruling lines with all the surface normals along any ruling line being parallel. This is a fundamental property of developable surfaces.
The algorithms for DevSrf and DevLoft appear to be based on determining lines between the two input curves such that the direction of the vectors are each end of the line normal to both the line and input curves are parallel (within a tolerance). The algorithms determine a suitable number of ruling lines, and then create a surface using the input curves and the ruling lines. I do not know the details of the code.
For a method using standard Rhino commands to determine exact ruling lines between curves which satisfy the no-twist condition see Developable surface - exact ruling lines from edge curves
For a method to check on twist between ends of a ruling line see Ruling line from edge curves twist check