1,417 karma · joined November 30, 2011
vmeznaric@outlook.com
Working on AI 3D modeling software - https://grandpacad.com
X.com/otivdev
Really exciting stuff is happening literally every month, because underlying models are getting better and better. When I started it was pretty basic: “make a cube with a hole through it”. Now it’s at the point “make a raspberry pi 4 case” and the agent searches, builds, verifies…
What surprised me in this process is how little meaning AI benchmarks have. Pareto frontier for my use case looks completely different than any other benchmark portrays.
And this kinda makes sense. What is cheaper few KB of disk space or internet bandwidth?
Comparing 4.8 Opus with Fable 5.1
Recently we also got European funding and the project got some traction. Very exciting times ahead.
> Using a single LLM judge for scoring. Every score here comes from one model, GPT-5.6 Luna, looking at one image at a time. I didn’t do much alignment and didn’t check how often it agrees with itself on a re-run.
Having used a similar setup (with previous gen LLMs) to evaluate the 3D models that my product[0] generates, it turned out there was no correlation at all. LLM judgments were very much random and I assume judging SVGs is not that far from judging 3D models. I guess I have to re-test this with current gen.
Edit: Surprisingly very good results with 3.0 flash with high thinking.
Cost: $0.06
Duration: 3.22 min
Code Errors: 1.3 per attempts (meaning on average it had to retry 1.3 times)
Adherence was on par with 3.5 flash Low thinking
I was benchmarking using a soon to be released new version of my AI CAD modeling software[0]. It's basically an agent that has access to tools that can execute build123d scripts, get sculpted models, blender to combine sculpts + parametric models, tools to inspect the model (visually and with code), search datasheets, ...
I tried what you recommend a while ago (asking an AI to evaluate using different angles) and the AI evaluations were extremely bad - barely any correlation to what I scored. Things have gotten better, but I don't trust it enough yet.
Here is how I score adherence (and how AI did as well, but I tried methods where it would just give back a boolean "pass" or not):
<0.2 → Poor – Misses core intent; largely irrelevant or incorrect.
<0.4 → Weak – Partially relevant; significant omissions or errors.
<0.6 → Fair – Covers main points but lacks completeness or precision.
<0.8 → Good – Mostly accurate; minor gaps or deviations.
<=1.0 → Excellent – Fully aligned; precise, comprehensive, and faithful to intent.
Here is the scenario list (prompts are much more detailed): dragon-bottle-stopper
editing-param-mid-conv
editing-parametric-enclosure
editing-swap-material-param
editing-text-edit-cube
multi-turn-bird-house
multi-turn-dice-tower
multi-turn-modular-planter
multi-turn-phone-stand
multi-turn-shelf
one-shot-bookend
one-shot-cable-clip
one-shot-chess-queen
one-shot-coaster
one-shot-coffee-cup
one-shot-dog-tag
one-shot-dragon-figurine
one-shot-hex-bracket
one-shot-keychain-fob
one-shot-low-poly-tree
one-shot-pegboard-hook
one-shot-pi4-case
one-shot-threaded-jar
[0]: https://grandpacad.comHere are the results compared to Gemini 3.5 Flash:
Model + config CodeErr/gen Cost/gen Median time Quality
gemini-3.5-flash, low 0.71 $0.18 68s baseline
GLM 5.2, reasoning high 0.61 $0.18 289s -6.0%
GLM 5.2, reasoning off 1.52 $0.10 126s -13.6%
Although it is cheaper, it is significantly slower, and results are worse overall. Surprisingly - high reasoning produces less code errors than gemini 3.5 flash, but when I actually look at the models they are worse.Edit: I recently ran evals with Kimi 2.7 and MiniMax-M3 and this is clearly open source SOTA model, by far.
Article ends with this
- Models are very jagged (might excel in one type of 3d model, but not another)
- Gemini models are the least jagged in my experience and have the best image understanding
- Gemini models are also the most creative (which may be undesirable if you want precise CAD part)
- Overall this benchmark doesn't prove much because one 3d model (and one attempt) is just not enough. I am usually testing on at least a dozen models each generated 3 times, but should really do much more, but it's too pricey for a solo dev.
Still, thanks for publishing this. Will be definitely run flash 3.5 soon to see how it performs.
Maybe it’s better in one particular case here and there and I think this blog post is example of that.
I have been working on GrandpaCAD[0] for a while, a very similar product. I thought of you as my biggest competitors but noticed recently you are focusing more and more on professionals while I am focusing on total noobs in modeling who just want to whip out a quick model. So I guess we are not competitors anymore?
My evals[1] show that Opus 4.7 and GPT 5.5 are very comparable in terms of generation quality, but GPT 5.5 is slower and costs sooo much more in my harness. And the original breakthrough model was Gemini 3.1. I'm curious do you have more written about your benchmarks setup?
If you want to chat email is in my profile. Btw, just met "your"(?) neighbour on a plane a couple of days ago. World is small.
[1]: https://grandpacad.com/en/blog/public-benchmarks-misled-me-o...
Anyone curious in the writeup? I have a pretty good harness for evaluating 3d generation performance.