70 MB object, 15,000 surfaces, valid, closed solid polysurface viewable only in wireframe. Hangs when I try to save as STL

Hi all:

In Rhino 6 SR26, I’m working on a 1:32 model locomotive and I’m currently designing the walkways with their non-skid metal plates with lots of embossed detail. A zillion surfaces, huge object size with a relatively small part – there’ s probably a much better way to do it.


I’ve created earlier versions of these pieces and had them printed. Now Rhino balks at creating them — sometimes it just hangs – and when it does create them, they are viewable only in wireframe and useless as producible models.

Any ideas what I might be doing wrong? I was thinking I’d just go back to the previous service release if that’s possible since it seemed friendlier to what I’m trying to do.

Hilary Smith
Pacific NW

Hi Hillary - by this do you mean it does not want to write an stl file? Or is there some part of the modeling process that hangs up?

@mrhsmith8 sorry, I just re-read the title of the post, that has more info than the contents! Run SelbadObjects and see if anything turns up - if so, ExtractBadSrf and see if you can fix the problem - very often it is a matter of retrimming.



I try to save the file as an STL and it hangs up – sort of. It took 10-15 minutes for Rhino to create the STL. Also, Rhino will present the ghosted view – after 15 minutes.

Thanks for the lightning response.

Hello - and does SelBadObjects find anything?



Hm - then I think you have your work cut out for you… I would try to chase it down by.

ExtractSrf and window around half the model. Join.
Does either half shade better than the other, in a shaded viewport? If so repeat the above, cutting the ugly bit in half each time to try to find surfaces that cause the problem.

My guess it there is a loop in a trim curve someplace and it is making the mesh wrong or hard to create.


Hey what are your export settings? can you take a screenshot?
Ive had issues with heavy models, esp with lots of triangular shapes before… (sounds like your antislip)
Do you use any other softwares?
In cases where I cant get something out of rhino, I find it might be easier to export via SAT / STL to 3DSmax, then adjust mesh via body object before exporting for print.

Hope that helps!

@Pascal. Thank you. I work on it and I’ll let you know when I find some happiness.

@Da da!: I appreciate your suggestion. Let me look into it.

Hilary Smith

15000 is not a huge number though. It might be related to Mesh generation.

I used to work on a BRep with 1M surfaces and exporting it to STL took ~10s

Good to know. Thanks.

Hilary Smith