GH Offsetting Brep Surfaces

I’ve yet to mess with anything like this in GH. In the however when I’ve modeled in Rhino directly specifically to utilize Unrollsrf I’ve had good success. Pretty old project done in rhino attached for reference. My goal is to get back to this level of use through just GH so if you have any references I’d gladly take any leads in that direction. Ideally I don’t want to lean into a workflow that works in GH, needing to bake a structure, and putting that structure back into GH so I’m keen to try and figure this out.

I’m still spinning my wheels a bit with this offset for the time being. I tried sticking to the curves themselves, offsetting them individually and just doing two separate lofts (one for the facade, one for the soffit) but this didn’t work.

On a simpler geometry I’ve used the offset in the sasquatch plugin which was used in Quan’s code without issue and then added joint lines across the offset geometry. For simple walls (no fascia-soffit transitions) I’ve enjoyed paneling tools. The intersection grid make alignment cake.

image

Something like this for reference.

It was a much simpler geometry without profile changes in Z axis so so I was able to do a face of panel based on the substrate, and cut the panels to size. Coping and flashing were simple sweeps.


I’m actually not a fan of creating solids in this case. When a Brep is created, then modified (Boolean operation) the face order isn’t consistent, with surfaces you can maintain your edge order, which is going to be needed further along in the process.

We should break this into the various steps of process.

Roughly…

  • Estimating

  • Shop Drawings

  • Fabrication

  • Install

One of the most powerful aspects of Rhino/GH is the ability automate alongside manual fixes to one-off conditions.

Are you familiar with Elefront? Elefront 4.x Essentials

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base model hilton.gh (78.2 KB)

This one is not based off of a point cloud. I was trying my hand ad creating a model from (0,0,0) for shop reference. Currently CAD is handling my workload for shops. My goal would be to create a model that could be adapted from shops to fabrication.

I came across it and downloaded but I have not messed around with the tools yet. Based on name alone I didn’t come across any components that leaps off the page as a solution to my problem with my limited knowledge. Seemed like it had a lot of nice annotation components but admittedly my goal with a model is to use section tools to export to CAD for my annotation of sections and make 2-D for elevations, and kick that over to CAD for annotation. I like to think I’m very quick in CAD. I’ve relied on hotkeys and a bunch of lisps to plug away at architectural drafting for years now. So until I can circumvent that workflow in Rhino from a professional aspect I can’t pick up shop and completely transition to a new platform.

Are we still talking about offsetting BREP?
If yes, this looks just fine.

Kinda, but my comment was more so related to -I’ve done this in the past on a simple geometry (and is the result I want for the project in question), but the same application of the tools is not working for the current complex brep.

I hear ya, small bites at first. If you’ve got a good system going that gets the job done and you can’t spend countless hrs twiddling with grasshopper to generate what you’ve got a consistent process for.

Quan Li is right, we should keep this on topic. When you get to particular questions create a post and we’ll work through it then.

Here is how elefront was used to create over a million parts and drawings. Go to 56:45 of the video.

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This looks brilliant, but after watching the presentation (stopping at fabrication, seemed unrelated to GH) I’m not sure what to do with the just knowing this exists. The video doesn’t describe how eleFront is used, and checking out their website I don’t see any starting point for learning the tools. New Features are commented on, but I did not come across any starting point. Feels like signing up for a gym to get back in shape and the personal trainer saying “ok lets start with piston squats”… while the end goal might be pistonl squats isn’t no place to start training. I’m lost and not sure how to apply this to my situation.

Forgive the wall of text but I think it might be valuable since I don’t think we’re on the same page. I appreciate any help but the possible solution presented by Quan Li I did not agree with because the solution required additional steps and the model I have directly when I opened the code did no look like my intended result. Could be I’ve messed something up again but all I did was open the link in a fresh file.


I can get behind creating something in GH, backing it in GH and referencing back in another file. Makes sense and you don’t loose the transparency having everything linked together. Which is one of the biggest appeals to GH from my perspective. I love the idea of having a model referenced to different components so that if I change “X” and “Y” is linked to some component of “X” then “Y” will update accordingly. Like I said, I like to think of myself as a fast drafter in CAD… and myself nor anyone on the planet is faster than a processor so long as you are knowledgeable enough to know how to frame the correct inputs. I lean into automation wherever possible in my continuing education. Take for instance in the composite panel world there exist a CAD extension that will unfold draw all parts for CNC (tooling lines, pilot holes, etc). It’s brilliant and I want to know how to do similar things in GH because it’s abundantly clear the tools exist if you know what you’re doing. Really, hats off GH is amazing and will change or already has changed the field. Anyways…

I don’t want to loose transparency manually drawing three dimensional shapes because if anything changes, it’s time to redraw. That is the step I’m trying to skip by investing time into learning GH. Redrafting is one of the biggest time sinks we grapple with in drafting. Related to my experience this is the selling point for why is GH useful. I can’t express enough how interested I am in learning these workflows to prevent redrafting of complex systems.

That said, how is this related to my original question. Forget the offset, whatever tool fits the purpose is what I’m after. I started with offset because I figured if I can model the surface of the substrate in question I can offset this surface based on the system depth and be done. It has worked on simple surfaces but not this one. Extrude is out, because it wont follow perpendicular to the faces so next step seemed to be try a sweep. The sweep seemed close to to what I was after but it also had issues. Currently I’ve been messing around with trying to just create a wireframe of the desired surface (knowing that if I can create the wireframe I can model a surface within).

Maybe I should rephrase my question to be something along the lines of -How would you create a clean surface based on a rail? or wireframe? or surface? I’m uncertain how to phrase the question.

I started by using the point cloud to define points on the face of substrate (specifically near the corners) and reset their Z axis to a common elevation. The next step was to connect the points at either end of the substrate and visually check for clashes (I’m sure there’s a way and it would be pretty trick to convert the point cloud to a mesh, or try that shrink wrap, and then check for an intersection along that surface to curve interaction. That would be… insane, but not the point of this post). After manually checking for clashes and agreeing that this is a “good” line, the lines are extended to provide corners and a polyline was created that would be my “plan cut”. I then moved the points as needed in elevation. Once I did that I used a number off surface tools (and some that output a brep and not a surface?). This last step is where I seemed to have gone off the rails since the outputs to not work feeding into new components.

So how would I go about not making this mistake to get where I want to end up? The end goal is to produce the surface curves for a panel system 2" from the face of substrate shown in the point cloud (or to say 2" from the wireframe/surface model provided)

You’re off to a great start in GH, i don’t want to sidetrack you with potentials, those will become clearer to your particular workflow.

In this case where you are drawing Breps to section it may be more complexity involved than necessary by using grasshopper, being such a small project with lots of unique conditions. Having a few references created from the cloud and drawing using Gumball Extrudes, etc would make quick work of it.

With this example in particular I am only responsible for the substrate dimensions while the panel fabricator will be providing panels based on our measurements.

My interest is modeling the face of panel in GH is only educational at this point for future use. Any recommendations for completing this problem in GH would be helpful.