[Blender] Making my first game asset isn't easy - troubles with retopo and UVs

Worraps

Hello everyone.
Few days ago, I opened this thread https://polycount.com/discussion/comment/2734111#Comment_2734111 concerning the basic pipeline to follow when you want to make a game asset. I've received the answers I needed to start a project and try to follow the "checklist" of the 3D Game Artist. BUT of course I'm a newbbie and, you can guess if I'm here, I encountered somes issues. 
I base my project on this link : http://wiki.polycount.com/wiki/Texture_Baking, I know I won't necessary have to do each one of theses steps, but anyway I'm already stuck to step 3 x) Looking back, I might be gone a bit too far with the details and the complexity since this is my very first attempt following the game asset workflow, but I have hope once I will have completed it I will have learned a lot ! 

So here is my High-Poly mesh made in Blender : 
I tried to retopologize, then UV and test some normal baking with Blender internal tool, and I quickly saw it was absolutely terrible, be prepared ( Yes this is a 4k normalMap) : 


So after that big failure, I came back here and read anything I could find about Normal Baking, UVs and LowPoly from HighPoly. So I quickly understood that I had to start over the step 1, after the HighPoly modeling, because the first of my problems was that my lowpoly geometry was too lowpoly and not close enough from my highpoly mesh, especially for all these cylinders. I know I have also done a terrible job while UV unwrapping, but this will come in a second time.

So the first time I tried to make my lowpoly model, I duplicated my HighPoly, applied all the modifiers ( including Array, Mirror, bevel... ) and started by adding a plane, by enabling face snapping and adding a shrinkwrap modifier just to be sure, and I made the "lowpoliest" model I could. But I wonder : should I instead of applying my modifiers, keep them and use them on the lowpoly model until the very end, so I dont have to retopologize and then UV unwrap the same object 10 times since I use some Array modifiers ? More obvious, my model is pretty much symmetrical and I use a mirror modifier for most of my part, can I just... retopologize and UV Unwrap only a half of my model THEN apply the modifiers once I get to the baking step ? I think I spent 2 days on retopology and UV, but I guess this could have been way faster if I had not applied my modifiers and used them ? Now that I want to start it over, I'd like to do it the most efficient way. And just to be sure : do we agree that my lowpoly shading must be flat ? I mean, I don't have to turn on the smooth shading since this smooth effect will come from the normal map adding all these fines bevels and details from my HighPoly Mesh ? 

Also, I know my baking troubles aren't due only to the lowpoly model, but this is the first step I've done wrong, so the others parts will come later, and this is also why I opened this thread because despite reading the ressources like https://polycount.com/discussion/107196/youre-making-me-hard-making-sense-of-hard-edges-uvs-normal-maps-and-vertex-counts#latest  there are still some concepts I need to clear...

Thank you for your time

Worraps

Ghogiel

Yes don't UV more than you have to, so if you can cut the mesh in half and cut up some UVs, then mirror it back and do a final UV layout, you'll save time. Same with any array

"do we agree that my lowpoly shading must be flat ? I mean, I don't have to turn on the smooth shading since this smooth effect will come from the normal map adding all these fines bevels and details from my HighPoly Mesh ? "
Smooth/hard shading doesn't add/remove details like bevels and details from a high poly. Be careful here, because you are absolutely going to have strategically smooth/harden edges of your low poly. Turning it off entirely and hardening all the edges of the low poly is the primary problem with your test bake image you showed.

I can give you an example, the circumfrence of the pipes should probably be smooth shaded and be made as continuous UV island. The Box that the pipes insert into, will probably do with a hard edge where there are 90 degree angle changes and split UV shells.

refer back to the stickies in this forum for more info on why.

Worraps

Hello ! 

So the last few days I've been trying to figure out what was going on with my bake and what was I doing wrong. First, thank you @Ghogiel
my main issue was indeed my misunderstanding of the how the shading worked. Instead of trying to retopo and cut my seam on all the model at once, I tried parts by parts, with different UVs sets : 1 for the main body, 1 for the big reactor, 1 for the front of the car and 1 for the rest and the details. Maybe that's too much, but I'll do better for my next projects. Also, I've added hard edges and UV seems following the stickies advises in the forum, and everything works wayyyy better. But i still have one question, and I hope I won't be burnt alive for asking : since flat zones are shaded... flat, what is the point of having good topology ? I mean... ngons and triangles are shaded correctly in theses spot, so, when I have let's say a big ngon resulting of a boolean operation to substract a cylinder from a cube, do I really have to fiddle my geometry until I get quads everywhere around the hole ? Because it will be flat shaded anyways ! Please don't kill me if that sounds dumb. 

Worraps

Ghogiel

Worraps said:

 since flat zones are shaded... flat, what is the point of having good topology ? I mean... ngons and triangles are shaded correctly in theses spot, so, when I have let's say a big ngon resulting of a boolean operation to substract a cylinder from a cube, do I really have to fiddle my geometry until I get quads everywhere around the hole ? Because it will be flat shaded anyways ! Please don't kill me if that sounds dumb. 

Worraps

Fact is, quads and ngons are alreadly tris. When it comes to a discussion of the surface shading of a poly model, there isn't any difference between them as far as shading is concerned as it's all tri under the hood anyway.

There are many kinds of modelling that serve different purposes though. Some times, as you are figuring out, quads might not be all that relevent to what  "good" topology might be in a particular situation. There are other concerns in different models that serve a different purpose, like a subdivision high poly, where quads are your friend. Just be aware that a ton of tools and operations like quads.  selection tools, UV flattening, skinning, etc are better fed with a decently built mesh with mostly quads. Don't make it hard on yourself and use quads when it makes sense and because it's also easy. Generally just making a model in a normal efficent way will result in mostly quads just by shear virtue of how modelling tools work, so you don't have to do much besides model normally.

If an ngon or tri isn't a problem, then it's not a problem.

Worraps

Hello, 

Thanks to your advises and tips, I'm getting somewhere. I found my way trough this hard baking process, and I'm slowly getting the concept about what good topology is, what good shading is, and all that need to be done properly. Sometimes you can get like 5 differents explanation for a concept and you still don't get it until you have tried it, practiced it. Thank you very much @Ghogiel for your time and your help ! 

If you want to see the uptade of this project, that will now happen here https://polycount.com/discussion/221943/wip-kinda-cyberpunk-foodtruck#latest since I consider most of my big technical questions are answered. 

Have a great day