3D Printing Effect? (Grow mesh)


Hello everyone,
I’ve scoured the internet the past few months and done a lot of experimenting in Maya, but still have not found a good way to animate a time lapse 3D print. AKA - “grow” a complex mesh.

Booleans are the obvious solution. The problem is that the models I’m dealing with are very poly heavy and UV unwrapped. I made booleans work in the past, but it was very painful. And can completely destroy a UV map.

Another alternative I found was the Cut Faces tool. But, it seems they changed the tool in Maya 2016 and it’s essentially equivalent to a boolean now. Also, it doesn’t play nice if there are cavities within the mesh.

A third alternative is to use animated masks on the shader. The problem here is that there is no way to add thickness and a “print surface” to the mesh.

I thought maybe the hard-mesh plugin would be a good option, but they seem to have disappeared. http://www.hard-mesh.com/

Any ideas, workflows, plugins, etc? This is an effect that I’ve already had to do a couple times and I know I’ll need to do it again in the future.

Surely I can’t be the only one??? How do you guys accomplish this?


Do you mean modeling booleans, or rendertime booleans?

Rendertime booleans are standard in even the cheapest software, but not in Maya of course. Vray can do it however:


Would something like that work? Are you using mental ray or Arnold for rendering?


Wow, yeah that looks perfect! Yes, I was talking about modeling booleans. I hadn’t heard of render-time booleans before. Thanks!

I’m using Arnold for rendering. As far as I can tell they don’t have an equivalent to VRayDistanceTex?

EDIT: After reading that blog post more thoroughly, the shader network seems pretty simple. Surely there’s an equivalent in Arnold? Any ideas?


As a completely different approach more less “really re-building the mesh” perhaps MASH might work?!



I experimented with MASH a little bit. There are some options to do similar effects using the explode node (I think).

I’m at a loss of how to preserve the UVs and add thickness - so the edges aren’t just paper thin as the mesh grows.


Happy Holidays everyone.

Any ideas for render-time booleans in Arnold?


bump…any ideas? I haven’t found any information about render-time booleans in Arnold. Maybe there’s a way to build that shader network manually?


So I was able to get close by plugging a clamped Ambient Occlusion node into the opacity attribute of the shader…but still no luck.

If there’s a shading expert or advanced scripter out there, I’d be interested in hiring you to work on this. It’s something clients repeatedly request and I have no good solution.

This effect could also be used for cutaways for complex meshes in technical visualizations.



I know you’re using Arnold, but if you get frequent requests for cut-aways etc it might be worth considering VRay for such work, which has the perfect tool for rendertime cut-away effects: the VrayClipper



sigh You’re right.

VRay has been poking at my brain for years. I avoided it because of time to learn and cost…just getting tired of switching renderers. Arnold is so simple and so fast compared to Mental Ray.

Thanks for the advice.


Maybe ask the arnold guys if they could implement it. Other renderers have it (CGS), vray, rman, maxwell…

Polycut still works as it should (i’m on 2016ext2 linux), maybe the ‘fill’ hole you use afterward can screw up, but it seems fine on my machine, even on heavy geo (million+)

If you want a try fun stuff with polycut: https://berniebernie.fr/wiki/Maya_Mel#.27Julienne_cut.27:_multi_polycut_across_shapes


I’m using both Arnold and VRay, and personally I dont find Vray any more complicated to work with these days, particularely since v3.

Just download the demo and have a look.


PS: In case you just what to check out if it does what you need before you spend time with new software, here’s a link to the doc page for the Clipper https://docs.chaosgroup.com/display/VRAY3MAYA/Section+Clipper+|+VRayClipper, plus ChaosGrp has a video on Youtube featuring the VrayClipper. Its in Max, but works just the same in Maya. https://www.youtube.com/watch?v=DLRzW6ixopI

Some pretty cool scripts you’ve got there on your page. Thanks a lot for sharing. :slight_smile:



Thanks Bernie,
I took a second look at the polyCut command. I guess they didn’t change the tool, but regardless it’s still painful to animate. The Fill Hole operation also doesn’t work if the mesh has cavities in it. Ideally I’d like a non-destructive workflow so I can make changes to the mesh without breaking everything.

Thanks for forwarding your scripts page. Added to my Maya Resources folder :keenly:


Thanks Razor,
I downloaded the demo yesterday and poked around a bit. I love the GPU acceleration.
But, I do miss the simplicity of Arnold’s sampling settings and the alSurface “uber-shader”…

Both clipper and VrayDistanceTex are very nice tools. I’ve got a couple of projects coming up this year that would heavily use them. We’ll see…



No Problem!

Btw, Vlado “partially” ported the alSurface shader over to Vray. Check here For info: https://github.com/ChaosGroup/vray_al_surface

and here for the files: https://github.com/ChaosGroup/vray_al_surface/releases

Good luck with your projects!



greetings from the future!

If you are still in need of this feature it is now a part of Arnold! The node aiClipGeo will do the trick for you.



Thanks! I learned about that node in this video from Arvid awhile back, but haven’t had a reason to try it out yet.