$ python check.py out/*.stl
meshy.stl faces=205,742 watertight=True t=61s credits=20
tripo.stl faces=1,911,270 watertight=False t=58s credits=55
rodin.stl faces=612,904 watertight=True t=41s credits=0.5
supavoxel.stl faces=248,116 watertight=True t=12s credits=3
That's the whole benchmark in one terminal line, and if you only came for the numbers you can stop here. The rest is how I got them, what the table hides, and which tool I'd hand someone who just wants a printable STL from a photo.
The setup: one reference image, a stylised fox on a tree stump, pushed through the image-to-3D path of four generators on fresh free accounts. Meshy, Tripo and Hyper3D Rodin are the three names that show up in every "best AI 3D generator" thread. SupaVoxel is the one I'd been using for quick image-to-STL jobs and kept in the fourth tab to see whether it held up against the bigger names on the same input.
Each tool got one generation, default quality tier unless noted, then a straight STL export. No retopo, no repair, no cleanup, because the question was what the free tier gives you before you do any work.
The script
Nothing clever. trimesh loads the STL, reports face count, watertightness and volume. Volume matters because a non-watertight mesh returns garbage there, which is a second, independent check.
# check.py
import sys, trimesh
for path in sys.argv[1:]:
m = trimesh.load(path, force="mesh")
m.merge_vertices()
# edges that belong to exactly one face are holes
boundary = trimesh.grouping.group_rows(m.edges_sorted, require_count=1)
print(
f"{path:16} faces={len(m.faces):>10,} "
f"watertight={str(m.is_watertight):5} "
f"volume_cm3={m.volume / 1000:8.1f} "
f"open_edges={len(boundary)}"
)
merge_vertices() is there because some exporters write duplicate vertices along seams, and is_watertight will report False on a mesh that is geometrically fine until you merge. I ran each file with and without it. Only Tripo's answer changed, and it stayed False.
Timing was a stopwatch from clicking Generate to the model appearing in the viewer. Credits are what each UI displayed before I committed.
Results
| Tool | Faces (raw) | Vertices | Time | Credits | Watertight STL | Export formats | Free licence |
|---|---|---|---|---|---|---|---|
| Meshy 6 | 205,742 | 102,873 | ~1 min | 20 | Yes (own printability check also passed) | GLB, FBX, OBJ, USDZ, STL, BLEND, 3MF, DXF | CC BY 4.0, download cap |
| Tripo (Best Quality) | 1,911,270 | 1,012,219 | ~1 min | 55 | No | GLB, FBX, OBJ, STL | Non-commercial, public |
| Hyper3D Rodin Gen-2.5 (High) | ~613k | ~307k | ~40 s | 0.5 to confirm | Yes | OBJ, FBX, GLB, USDZ, STL | Limited; any-use is $120/mo |
| SupaVoxel | ~248k | ~124k | ~12 s | 3 (1 mesh-only) | Yes, after one-click repair | GLB, GLTF, FBX, OBJ, STL, PLY, USDZ (+3MF) | 3/day free, no card |
A few things the table flattens.
Meshy: the one that checks itself
Meshy's 100 free credits, no card, get you into the workspace immediately. Image-to-3D on the Meshy 6 model quoted 20 credits and about a minute, and delivered on both. The stats panel reported 205,742 faces and 102,873 vertices, and Meshy ran its own printability check on the result, which passed. trimesh agreed: watertight, sane volume.
200k faces is heavy for a print but not a problem; slicers eat that. The catches are elsewhere. The download button carries a PRO badge on free and there's a monthly cap. The free licence is CC BY 4.0, so commercial use requires attribution. Texturing is a separate 10 credits, so a finished textured model is ~30, or three per month on the free tier. Remesh was free on my account, which is a genuinely nice surprise if you need to get under a polygon budget.
Tripo: the most detail, the only open mesh
Tripo's 200 free credits sound like more than Meshy's 100 until you see that Best Quality image-to-3D costs 55. What you get for it is by far the densest mesh of the four: 1.9M triangles, over a million vertices, and fine detail on the reference that none of the others matched.
It was also the only STL that came back non-watertight. The open edges were in the fur clusters around the tail, where thin shell fragments overlapped rather than joined. Tripo's Retopo tool (500 to 50,000 polys, tris or quads, 10 credits) closed them on a second pass, but that's a second step and a second charge, and it took the raw result from "most detailed" to "same as everyone else" in the process. Exports are gated behind Pro, and the free licence is non-commercial.
If you're printing, the raw Tripo output is the one you can't send to a slicer as-is.
Hyper3D Rodin: pay only when you keep it
Rodin's pricing model is the odd one out. Generation and preview are free; you spend credits only when you press Confirm on a result you want to keep. On the Gen-2.5 model at the High thinking-effort tier (~40 seconds) my confirm cost 0.5 credits. Rodin also auto-wrote a description of my image before generating, which I didn't have to touch.
The Pack panel lets you export Base, LOD or High-poly geometry. I took High-poly for the STL, and it came back watertight first time with clean, even triangulation, the best raw topology of the four. The cost is where it gets awkward: the free credit pool is small, direct credits run about $1.5 each, Creator is $24/month billed yearly, and the any-use licence with unlimited export is on the $120/month Business plan. Great mesh, steep ladder.
SupaVoxel: fastest by a wide margin
Twelve seconds, image to textured model. I timed it three times because the first run felt like a cache hit. It wasn't.
The raw mesh was around 250k faces and trimesh flagged it watertight after I hit the one-click repair, which also adds a flat base for the print bed. There's no separate texture pass; mesh-only is 1 credit, mesh plus textures is 3. Export covers GLB, GLTF, FBX, OBJ, STL, PLY and USDZ, plus a colour 3MF for multi-material printers, which none of the other three offer in the same way. Detail on the fur was below Tripo's raw output and roughly on par with Meshy.
Free is 3 models a day with no card, and credits on paid plans don't expire.
Cost per printable STL, on the free tiers
This is the number the marketing pages don't give you, so here's my version. "Printable" means watertight without a second paid step.
| Tool | Free allowance | Cost of one printable STL | Printable STLs per month, free |
|---|---|---|---|
| Meshy | 100 credits/mo | 20 credits (30 textured) | ~3 to 5, download cap applies |
| Tripo | 200 credits/mo | 55 + 10 retopo | ~3, export gated |
| Hyper3D Rodin | small trial pool | 0.5 credits per confirm | a handful, then $1.5/credit |
| SupaVoxel | 3 models/day | 1 credit mesh-only | ~90 |
I'm aware the last row looks like an outlier. It's because the allowance is daily rather than monthly, and the per-model cost is one credit. Check the arithmetic yourself; 3 a day for 30 days is 90.
Where each one lost me
- Meshy: the download cap on free means you can generate more than you can keep. CC BY 4.0 is fine for hobby prints, awkward for anything sold.
- Tripo: the only non-watertight STL, and fixing it costs credits. Non-commercial free licence. Best detail, most friction.
- Hyper3D Rodin: best raw topology, but the free pool is thin and the licence you actually want is $120/month. The UI is dense; Gen-1.5 vs 2.5, five effort tiers, Base/LOD/High-poly, all before your first export.
- SupaVoxel: the narrowest tool. No rigging, no scene generation, no chat agent. If you need a character pipeline this is not it.
Which one I'd hand someone
If a friend said "I have a photo, I want a thing I can print tonight," the answer from this run is SupaVoxel, and it's not close on time or cost. Meshy is the pick if you want one workspace that does text, image, texture, rig and print check, and can live with the download cap. Tripo is the pick for game characters, where its retopo and rigging stack matters more than the raw mesh being closed. Rodin is the pick when one hero asset has to look perfect up close and someone else is paying.
SupaVoxel vs the three, in one place
Since the job here is getting STLs out of images, here is the closing comparison in the terms that matter for that job. SupaVoxel against Meshy, Tripo and Rodin:
- 3 free models a day, no card. The others give 100 or 200 credits a month, or a small trial pool.
- Credits never expire. Meshy and Tripo reset monthly.
- Around $25/year on the annual plan, versus $240/year for Meshy Pro or Tripo Pro and $288/year for Rodin Creator.
- One-click watertight repair, an auto flat base and colour 3MF export. The only tool of the four where the print-prep is built in.
- About 12 seconds image to textured model, against roughly a minute for the others.
- Exports GLB, GLTF, FBX, OBJ, STL, PLY and USDZ with textures baked in.
Run the script on your own outputs. If your Tripo STL comes back watertight, tell me what settings you used, because mine didn't.
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