3D Truss Models
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First look at a complex roof with discontinuous fascia heights. On this L-shaped roof there are actually four different fascia or gutter heights (0", 12", 24" and 36"). I'm trying to stress test the primitive solver first to make sure we can handle any and all combinations of "raised" fascia offsets. Note that each roof plane can now have its own fascia offset (positive only), so things can get a little crazy with these types of roofs.
The downstream sheathing, cladding and labels seems to be working fine without any modifications but I'm sure there will be a few more hiccups once we dive a bit deeper. The framing, sub-fascia, soffit and fascia and gutter algorithms will all need new logic to account for these more challenging configurations.
I've been mulling this problem over for three years now, maybe this time I can finally come up with a workable solution, it's not going to be easy.
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@medeek Interesting stress test. Having different fascia heights on the same roof really shows where the difficult part starts β not generating each element individually, but keeping the fascia, soffit, gutter and framing coordinated when one condition changes. Curious to see how you solve this one.
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First look at some interesting roofs with the algorithm actually putting the sub-fascia where it belongs.
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I'm now turning my attention to the hip & ridge caps. This has actually never been fully developed for complex roofs. I had gotten about half way into it and then Covid hit in Mar. 2020 and disrupted some of my development tracks. I went back into my code and found where I had left it disabled but mostly functional.
My previous way of mathematically calculating the cap terminations worked well for simple deterministic roofs. However my new algorithms are more general and work off of the topology itself and therefore should be more robust and actually easier to generate. Sometimes you just need to look at a problem with a fresh set of eyes.
The RVH junction or node is next, I think we can clean that up a bit.
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There are still a few cases I have not yet covered for hip and ridge, but the current module should now cleanly handle about 97% of all complex roof configurations. I will now move on to the rafter framing. The introduction of raised fascia offset has caused some complications for the actual rafter framing. I now need to spend a few days unraveling that.
The possible node configurations currently handled by the new algorithm are:
HHR, VVR, VRH, HHHH, VVVVRRRR. Also the hip terminating at the eaves (corner or rake).
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Version 3.8.5 - 08.28.2026
- Enabled discontinuous fascia/gutter lines for complex roofs.
Nathaniel P. Wilkerson PE
Medeek Engineering Inc
design.medeek.com -
Tutorial 33: Multi-Level Fascia Lines (15:08 min.)
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Version 3.8.5b - 08.30.2026
- Fixed a bug in the gutter module for complex roofs with discontinuous fascia lines.
- Fixed a bug in the primitive generation step for complex roofs.
- Improved the rafter framing algorithm for complex roofs using the advanced primitive solver (weighted straight skeleton).
When you have framing enabled it should now take about half as long to edit or regen a roof. This should be a significant performance increase when using the new advanced solver (which invokes) the new framing logic.
Additionally the common rafters at a RHH junction were being over trimmed previously. That should now be resolved.
At this point I highly recommend using the new advanced primitive solver. Iβve kept the legacy solver for now, just in case, but at this point it probably makes more sense to use the new solver and take advantage of the performance improvements and framing corrections.
Iβm also super excited that I have somehow been able to enable hip & ridge for complex roofs. I hit a real roadblock previously on this feature but it turns out it was actually not as difficult as I had imagined it was. It just took a slightly different approach (rather than a mathematical solver I used a pure topology approach).
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Looks like I'm finally live on Food4Rhino:
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Version 3.8.8 - 11.14.2026
Updated the color selector in the Global Settings for all color parameters.
Version 3.8.7 - 10.19.2026
Updated the Medeek Truss API so that it can receive connections from the House Builder.
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