Wow, thanks everyone for the great replies to my questions. Your answers were very insightful and helpful to me.

@SurlyBird:

It is great to hear that others are using MoI successfully in their game asset creation pipeline. I checked out your web site and your game assets are top notch! Great work and I really liked the way you not only showed the end result but also the workflow that you used to achieve the final low poly game objects. I noticed that you are using Substance Designer for texturing and map generation…I just bought this application as well and think it will be the future of texturing (especially with apps that support it natively like Unity). I appreciated your explanation of the different techniques that you use to generate a low poly mesh from your MoI nurbs model. Just to summarize, it sounds like any of the following workflows would work (depending upon the complexity of the MoI object that you are starting with):

1) Export high-poly mesh from MoI to be used as basis to bake normal/ambient occlusion map for low poly object
2) Generate low poly mesh by one of the below methods:

- Simply export a lower poly mesh straight from MoI and use that “as is”
- Export a lower poly mesh from MoI and clean up the mesh in poly modeler as needed
- Retopo the high poly mesh in poly modeler to create a low poly mesh
- Build a “more simple” version of the nurbs model in MoI and export that simplified version to create a more game friendly object (this was a great idea that I didn’t think of)

@Michael Gibson

It’s great to see that the creator of the application is so active on the forums. Thanks for taking the time to answer my questions. The tips that you provided about techniques to avoid when coming from a subd modeling mindset were very helpful.

I understand that many people are extremely productive at hard surface modeling using subds, and while I can hold my own, it has never seemed as intuitive and easy as it should be. For me, subds force me into a mode of focusing so much on topology during the creative phase that I spend most of my brain power working out poly flow puzzles rather than just designing. I am going to buy MoI this evening and am excited to learn more about nurbs modeling.

To answer your question about what the Unity game engine expects…

Unity does not support the rendering of subdivision surfaces (most game engines do not) since they are processor intensive and not really appropriate for real-time game engines. Unity only accepts standard poly meshes (though it will honor smoothing angles). When Unity loads a mesh, the engine will triangulate all of the polys in the mesh (if all polys aren’t already triangles). Therefore, a typical workflow for someone creating a game asset for Unity using subd modeling would be: create high res subd model, create low res version of same model, triangulate the low res mesh in a poly modeler (it is better to triangulate yourself so your UVs and normal maps are optimal in Unity), UV map, bake normal and ambient occlusion maps onto low poly mesh (using the high res mesh to supply detail), texture, bake diffuse and specular maps, export low poly mesh (with uvs and all texture maps) to Unity.

Hi Tim,

> I understand that many people are extremely productive at hard surface modeling using subds, <...>

It can vary a lot depending on the particular qualities of the model - "hard surface" is a rather generic term...

If the objects being created have the overall form of something like one connected skin, then the sub-d modeling can progress in a similar fashion as it's done for organic models and it can go well. Things like space armor and vehicles can fit into this kind of stuff. These kinds of things can be in the sort of "gray area" that I was mentioning previously where it's not always 100% clear whether you'd want NURBS or sub-d for them and when that happens you may actually want to err more on the sub-d side especially if you're still getting up to speed with NURBS modeling strategies.

If the objects being created are more like engine parts that have a lot of holes in them, then suddenly the sub-d productivity level drops off a very steep cliff even for expert users. There is just fundamentally a tremendous amount of manual topology arranging work involved to try and accommodate precise holes when using sub-d, and it also gets easy to have a lot of imperfections like little bumps or ripples - those are often unwanted side effects when you're trying to force a sub-d topology into place that has to deal with a lot of constraints.

Check out this thread on the modo forum for a good example of this specific type of situation:
http://forums.luxology.com/topic.aspx?f=32&t=67986

There you'll see an example that's really clear, a whole lot of topology planning and just overall work needs to be done to do that in sub-d but meanwhile in MoI the same model is done more precisely in literally 20 seconds of work, see the youtube MoI screencap video that's linked to in the thread there.


So a lot of this depends on the particular qualities of the model at hand. When you get accustomed to using MoI you'll be able to recognize the kinds of things that will come together really quickly in it.


re:
> Therefore, a typical workflow for someone creating a game asset for Unity using subd modeling
> would be: create high res subd model, create low res version of same model,

So yeah it sounds like you've already got this figured out, but since you are not talking about retopo to produce quad topology for making sub-ds and are more focused on just making low poly, it is certainly worth a shot to just generate both a high poly and a low poly output from your same MoI model and see if that does the job for you at least for some particular cases.

NURBS models have a similarity to sub-d models in the sense that they define some "ideal smooth surface" and you can generate different approximations of that at export time, either high density or lower density output from the same base model.

- Michael

As I know, quad polygons only need where animation happens. So if I'm right for hard surfaces it's not necessary to have quads because hard surfaces do not bend like arms. And if I'm right it is possible to export from MOI High and low poly model for hard surfaces.

Hi Andrei, well it all depends on your own particular needs... it is pretty typical for hard surfaces to not animate by stretching or bending, they do tend to be animated by rigid body motion only and if that's the case then yes you're right.

But it could be possible for someone's particular project to need hard surfaces that bend and flex if they're going to try and make it move with some kind of personality or something like that... whether that applies to your specific project or not is something that only you can answer.

It's often better to base your requirements on what you are specifically trying to do. Ironclad abstract rules like "every polygon must be a quad" or the reverse don't really make sense, try to do what applies to your particular needs.

- Michael

hoi andrei!

for game props, engines and general game related modelling i would check out polycount.

http://www.polycount.com/forum/

tons of information in there.