GH Offsetting Brep Surfaces

I was directed to ask a my question here, I’m stumped. I’m unable to get my complex brep to offset. It has changes in elevation, arcs, and changes in profile. The brep appears closed but I’m concerned that’s not accurate after messing with some different offset tools. I’ve attached the baked output for reference, I’m not sure my code would be of much use but I’ve added it (though no structures will be generated since the point cloud would be unavailable)

I’m doing line work off of a point cloud, first step was to set a common Z axis for the associated points and play connect the dots with a continuous polyline to resemble a plan cut. Once I had the intersections I moved the points to the correct elevation and recreated a curve which would resemble rails or boundaries for a loft. I used several different components to get the “surface”. When I attempt to offset this clean substrate for face of panel (what’s being modeled in this case), it does not work.

My question would be do you have any recommendations for offsetting a surface like this, and are there any guidelines I should consider when structuring a similar surface?

surface.3dm (173.8 KB)
scan (438.4 KB)


Please read this very carefully…
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“I’ve attached the baked output for reference, I’m not sure my code would be of much use but I’ve added it (though no structures will be generated since the point cloud would be unavailable)”

Not sure what you’d like me to do here, max upload is 20mb and the point cloud is much larger than that.

Lets try to isolate the particular issue. Place a Brep component before the Deconstruct and Internalize the Data (Right Click).

Providing just this area and eliminating the various plugins will make it easier to help.

Currently we would need all these and the cloud to even begin to help.

scan (503.4 KB)

Is this correct?

Need this part of the GH to solve the problem.
What is the BREP and how did you make that.

Because if a BREP can not be offset directly, people will need to go back through history to find a solution. There is no magic button or plugin to offset a complex BREP directly.

And it’s better to show the failed attempts. With that, we can know your true intention.

So what you need to do to get better help is just show that part and delete everything else(including unpopular plugins) before sharing. Otherwise, people will feel overwhelmed and walk away.

This guideline is good and will give you maximum help.
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There are 3 totally separate geometries.
Which one is the BREP you are trying to offset?

All of them, hopefully together. I was attempting to generate a surface of the substrate conditions to be offset based on the system depth of the wall assembly (in this case 2") to identify panel sizes based on the other wall system already modeled.

The idea was, create a surface of the the wall, offset for the system depth.

edit: additional comment. I did join all the separate breps (via brepjoin) before plugging it into the offset provided but that seems to be part of the issue.

One thing you should look at is ShrinkWrap in the Rhino 8 WIP, which will work on Point Clouds. A QuadRemesh after can result in some decent geometry that you can work with. There is a Grasshopper component as well. Rhino 8 also has better mesh offsets (shrink wrap can offset as well)

Part 1 of 2 (how I got to the current brep)

part 2 of 2

I’ll have to give this another look. I dismissed it because I did not believe I would get my intended result. I’m trying to simplify the building substrate based on the point cloud data, from what I read I assumed I’d be covering the point cloud therefore retaining the imperfections in the wall.

You may have to clean your point cloud and segment to get reliable data (in any workflow involving pointclouds)

here is a offset script that works well, there are others in various plugins too.

scan (555.6 KB)

Thanks, I tried incorporating it, but did not get the intended result. I flipped the arc that was faced incorrectly and brought all the pieces in, result attached. I believe this script has made its way into one of the plugins I messed around with because I remember getting a rounded offset like this in one of my failed attempts. When you take that off and also toggle solid it does not function at all with the shape I have.

The issue in offsetting polysurfaces to a solid is the various possibilities that the intersections create, especially when non-planar curved geometry is involved.

Ok. Where does that put this problem? Are there other methods I can try?

I’m flying blind here and it all seems pretty magical for an outsider looking in trying to pick up GH. I assume there is “a” way, I just can’t figure it out because I don’t know what I’m doing.

I’ve stumbled my way through some other models without issue but the substrate on this one is the most complex I’ve faced. Just speaking to my experience in construction getting something like this to work consistently will be a massive game changer to releasing material for fabrication. Architects love aligning features, who doesn’t. Being able to see in real time the output through Rhino has already been a big improvement (to me). Previous methods involved cutting large numbers of section cuts, tracing them, then making corrections based on elevation as you fight to get a truly perpendicular view of the elevation in question over and over again until you’re comfortable with the result.

That said If I can’t complete the process from start to finish in Rhino, then I’m left with sticking to what has worked in the past. I understand this isn’t simple, but any lead in the right direction would be helpful.

scan layout Edited (72.5 KB)

Good morning.
This solution may need plugins.
The outcome is good but also has a few weird parts.
Those are caused by unmatching edges of the original surfaces. This is the reason one might need to go back through history to solve some issues. Try to trim off them manually in Rhino.

Thanks for the help, I’ll have to play around with it and get it working on my end. I’ll follow up when I have something to show for it.

To follow up with you a bit. How are you generating your panel unfolds and such? These fabrication workflows are popular around here, let me know if you have any questions.