I built my castle on shifting sands! I have a lot of work on a definition that is dependent on the deconstructed edges/points of one trimmed surface. I just had to modify the trimmed surface (changed the angle of one cutter) and everything went to hell because it shifted the order of every list. Rather than finding and Shift List’ing every reference to the surface (dozens and I may need to modify the trimmed surface again) is there a way to shift the order of the surface itself, prior to any deconstruction?
Never thought this would be a problem but I never stopped to consider how Grasshopper decides where to begin counting edges/points. I’ve learned my lesson on organization… dissect and label all the pieces of one Deconstruct, so you only need to rewire it once I guess.
Getting Shifted.gh (13.0 KB)
Your model is not adequate since it doesn’t show how you modified the surface?
That is part of the story, isn’t it? Sorry, I left it out. It’s minor but I pulled back the front edge. I tried a few different iterations of this, using the original cutting curves and (in this case) trimming the trimmed surface. All resulted in a different ordering of deconstructed geometry.
Trim Surface Modified.gh (14.3 KB)
You’ve been on this forum for five years and never run into these issues before? Your modified file still doesn’t illustrate the problem very well so I added sorting by area (yellow group) to get the correct fragment from the second SplitMul, then added Disc and Points (Point List) to show the effect of using Flip Curve or not. My only advice is “Deal with it”.
Trim Surface_2022Feb17a.gh (15.3 KB)
I added the additional information to be respectful, you asked so I delivered but that isn’t what my question was specifically about. When you deconstruct a brep, an order is generated, I was curious if you can alter that order before deconstruction. Similar you how to can flip a curve or a surface and that change is imbued into the curve/surface, I was wondering if you could shift the order of edges/vertexes.
Just dealing with it is fine, as I said, in a redo, I would Deconstruct, sort out and label a master list of the points/edges separately rather than using a new Discontinuity, Deconstruct Brep, and Brep Edge with the original surface for every operation. Rookie move. I wasn’t expecting changing an edge of a glorified triangle to shift all the points/edges of the said triangle, and if our vendor hadn’t made a mistake with our order I wouldn’t need to be hacking an edge off the original surface. That’s all okay, I can deal with fixing that, my question is in the title, and it was a curiosity.
