Converting a model into something printable

[TehOmbra]

Hey guys!
I recently got a 3d printer and am looking forward to printing out some armour. I have a game rip model, and am familiar with 3d modelling tools (though not particularily skilled). I plan to build up some detail on it based on how it's textured and split it apart into pieces small enough to print. I'm looking for some advice on how to do this. How do I determine what scale I should set the model to, what is the best way to break the pieces up into different pieces (chest, helmet, etc) and then further break it up into pieces that a printer can manage, and lastly, any tips on adding detail?
Thanks,
Ombra

 

[Termhn]

Unfortunately, this is not an easy process. In order to to 3d print, you first need to clean up the meshes and make each part into one solid, watertight mesh. This will either require a LOT of doctoring on game ripped models or just using those ripped models as reference and creating your own model from scratch, which is what I'm currently doing for the helmet I'm going to be printing. Then you'll need to split those into pieces... this is probably the easiest part, you can just use boolean operations or there's a couple programs made specifically to do this.

 

[TehOmbra]

Can't I just extrude inward to add thickness and throw that into a program like netfabb or something similar to fix the problems with it? Then used that fixed model as a base for building up detail?

 

[Termhn]

Can't I just extrude inward to add thickness and throw that into a program like netfabb or something similar to fix the problems with it? Then used that fixed model as a base for building up detail?

You could possibly do this if all the models were one solid mesh but unfortunately most of them are made of several pieces that just look like they're attached but they're really separate objects that intersect each other and aren't fused together.

 

[TehOmbra]

Looks like I got lucky with the model I chose, it came as 5 pieces, torso, two shoulders and two hip pads things. I went through and deleted all the under armour part of the character and separated each piece into it's own object (forearm, helmet, etc). It looks like I can extrude them and they all seem to be fairly happy about it (no crazy faces inverting or whatever). I haven't worked much with models built with triangles and the detail on the model is mostly done through textures, any advice on how to add more details to it and how to scale it to be appropriate human size? Here's a screenshot showing what I mean by it being all triangles and the detail being mostly textures.

 

[Termhn]

Yup, that's what they all look like for me too. I guess you got lucky with that piece that they're all already in one piece. Game models are generally in all triangles with detail "baked" from a high resolution model into the textures which the game engine can then use to fake the detail on a low poly model in a way that is much faster than rendering out a real high poly model. The topology of a game model is also normally not conducive to adding detail back in.. you could try doing a convert tris to quads operation but I doubt it will be able to convert the majority of them, and adding details with topology like that is going to be a PITA if not impossible. The way you normally get a model to look good and add nice looking details is by using subdivision surfaces or "subd" for short. This subdivides the mesh in a dynamic way and then you can add more topology where needed and adjust edge weighting to crease edges or make them smoother. However that is only possible with a model with good topology. In order to do that you need to manually remake the topology... it's somewhat of a complex process but it's not too hard. Try looking up retopology tutorials online.

One other option that I considered but haven't actually tried is using ZBrush.. by bringing them into ZBrush you could theoretically use ZRemesher and Dynamesh to get a more even, if not ideal, topology which you can then sculpt the details into using Zbrush's excellent sculpting tools. You can also export models directly from zbrush for 3d printing I believe.

 

[TehOmbra]

Here's a quick before and after shot of the model I'm working with. Asked an artist friend to add some more detail to it after I tried and failed.

 

[Termhn]

Nice! Looks like he sculpted on it.. I'm going to guess with Mudbox based on that shot.

 

[TehOmbra]

Nice! Looks like he sculpted on it.. I'm going to guess with Mudbox based on that shot.

Close, I believe he used zbrush. Now to try to clean it up a bit so that the edges are more straight and less organic which won't be fun.

 

[Termhn]

Close, I believe he used zbrush. Now to try to clean it up a bit so that the edges are more straight and less organic which won't be fun.

Hmmm... I would have said that but the Zbrush viewport doesn't look like that and it doesn't usually look like that in a render. Certainly possible though. You could probably ask him (if he's not sick of it already) to harden it up in zbrush, wouldn't be too hard. Or you could try it yourself if you have Zbrush or... acquire it in an alternative manner xD

 

[TehOmbra]

Hmmm... I would have said that but the Zbrush viewport doesn't look like that and it doesn't usually look like that in a render. Certainly possible though. You could probably ask him (if he's not sick of it already) to harden it up in zbrush, wouldn't be too hard. Or you could try it yourself if you have Zbrush or... acquire it in an alternative manner xD

He only gave me a .ma since he knew I had maya ): I might ask him to see if he can harden up the edges a bit for me but I feel kind of bad asking him to make changes to it. The whole beggars can't be choosers thing.