Multiple High Poly to a Single Low Poly Baking?

LatteIsHorse

Hi,

I am practicing modelling/baking and I've been having this question that I cannot really find an answer.

Is there any way that I can bake a single low poly from a high poly with multiple parts?

I've done baking 'bake by name' in substance painter.

But as I'm constructing quite a large space this time, I wanted to reduce the number of objects existing in parts.



For example, this is a chair that I modeled in parts - please ignore that it's unnecessarily high in poly, just practicing stuff.

Can I make a single low poly of this chair with all the separate parts baked without remeshing the high poly?
Or does the high poly model has to be properly collapsed and connected as a single object as well?

If possible, can you recommend me a nice workflow, please?

Thanks x

Ghogiel

Depends where you are baking the object, but you do not need to collapse any objects, high or low, to a single object. You can have 1 low poly object and the high poly consists of 50 high poly. Just add them to the bake list, no need to name match in that case since there is only 1 LP object.

But you probably want to have a couple low poly objects just to avoid any intersection errors in the bake. Depending on how the LP is constructed, if it's non connected geometry and sits very close to other objects, you probably still want to use name matching.

LatteIsHorse

I usually model in 3ds Max and Maya, and bake stuff in Maya or Substance Painter.

So, I can technically bake a single low poly from multiple high poly, but it's better to consist the low poly in multiple elements or do separate parts and use name matching if the high poly has overlapping faces even if the low poly is one connected entity?

I don't know if this makes sense but:

What if I were to bake a part of high poly model, for example the back of the chair only on the complete low poly model of a whole chair?
Would it only bake the high poly bit of the back onto the low poly chair or would it completely go wrong?
Is Maya or Substance Painter will automatically be like, 'Ah, that's the back of the chair, I'm only backing the back bit.' or completely get lost?

Sorry if I don't sound that clear, but I think I got clearer ideas on the part where you explained, thank you!

Ghogiel

LatteIsHorse said:

So, I can technically bake a single low poly from multiple high poly, but it's better to consist the low poly in multiple elements or do separate parts and use name matching if the high poly has overlapping faces even if the low poly is one connected entity?

If the low poly is one element and all the verts are welded together, there isn't anything to split. Just make sure the cage doesn't intersect with itself and the bake will be fine.

LatteIsHorse said:

What if I were to bake a part of high poly model, for example the back of the chair only on the complete low poly model of a whole chair?
Would it only bake the high poly bit of the back onto the low poly chair or would it completely go wrong?
Is Maya or Substance Painter will automatically be like, 'Ah, that's the back of the chair, I'm only backing the back bit.' or completely get lost?

It'll bake the everything not just the back of the chair part. What'll happen though is since the rest of the HP chair isn't there for the raycasts from the low poly to hit, it'll just leave a mess in the bake on everything that isn't the back of the chair.

LatteIsHorse

Thank you for your detailed explanation, I think I've got a clearer idea about baking in general.

Thanks again!

gnoop

Do anyone know   simplest approach to re-bake multiple low poly objects already having their own  tangent normal maps into a new shared /packed atlas  with each detail having its uv islands  getting new rotation/orientation, new pack?       I know Simplygon can do it but it's out of reach.      Blender can do it too   but it renders each object consequently, one above another. It often takes forever there  and you have to turn off padding  to avoid overlapping. And in general it's a pain  in .... there.

Can Marmoset do it  or Arnold in 3d max?  Maybe one of  Substances?   or Zbrush?      

Kanni3d

Marmoset can bake normals onto normals
You can also do uv channel transfers in 3DS max, which is probably safest since there's no projection baking that may introduce artifacting/skewing.
(If a tangent normal map has it's uvs rotated/moved/scaled in a new atlas/pack, it'll be fine. It's only object/worldspace normal maps that would break with new orientations.)

nessinby

Sorry for the Thread Necro, but this is what popped up in Google when I tried to remember what the specifics of Painter's Match By Name stuff. So, I'm going to leave the actual resource here for other peeps to find.

https://substance3d.adobe.com/documentation/bake/matching-by-name-182256530.html

kanga

You can also optimize a high poly model by deleting edge loops and leaving a bit more resolution on curved edges. I did that once for an entire city level. Using max at the time just applied materials to the parts and used that info in unreal. I only made models of the stuff and uved them if I couldn't find downloadable items like park benches and public trash cans in a compatible style. Pretty much all office assets were optimized 'free to use' excising models. The quality of the furniture was pretty high and I was amazed at the range.