Normal bake issue

Torch

Hey all, feel a bit n00bish for asking this but have been having an issue with normal baking for a little while, using Xnormal. Everything goes ok with the initial bake, the only issue is I have these nasty black lines where the seams are - kinda thinking I'm doing this wrong. Can anyone point out why this might be happening? I've checked the smoothing groups are sorted but still getting the problem. Thanks in advance

Tim270

If your smoothing and uv shells are ok(?), have you tried flipping the green channel in the normal map?

jeremiah_bigley

Did you use a cage when casting? If not then xnormal automatically breaks the cage where there are smoothing groups resulting in a hard edge bake.

BARDLER

Could you show your high poly?

Torch

Hi, thanks for the replies! I don’t think I used a cage, just the Ray distance (?) calculator before baking, that would most likely be the problem. I hardened the ‘top edges’ of the object where the bevels should be, if I soften them I get some mesh artefacting. Kinda new to baking with Xnormal, is the cage setup in tools? I’ll have a look in a min…

I can’t post a pic of the HP right now as am at work but will do so when I get home. Thanks all

EDIT: Just found this link on the Xnormal site (Ray distance method 2A) , will have a look at lunch -

http://www.xnormal.net/Tutorials.aspx

chrisradsby

Check out this one man:

http://www.polycount.com/forum/showthread.php?t=81154

Torch

Thanks for the link Chris!

So after doing some research including viewing those links, I started testing adding some 'support loops' and re-baking (just a test to see how it comes out,) getting much stronger results now:



Not sure how much of this I am doing right as I am still new to the process of hard surface normal baking, going to see how it goes

SsSandu_C

hmmm nope... I don't know why would you added those loops(ngon alert ) . In the first image you posted you had things kinda right... ofc you could have removed and reconnected some edges to reduce the tricount. I mean it is just a flat surface... no need for so many polys. What you need here is a combination of cage bake and offset bake. The cage bake for the edges of the object to appear good and the offset for the details that sit on the flat surface of the object. You should combine them and get a nice looking prop with the right amount of polys.

EarthQuake

Torch wrote: »

Thanks for the link Chris!

So after doing some research including viewing those links, I started testing adding some 'support loops' and re-baking (just a test to see how it comes out,) getting much stronger results now:



Not sure how much of this I am doing right as I am still new to the process of hard surface normal baking, going to see how it goes

I would suggest reading through the thread again, its kind of confusing bit it covers a lot of topics. It seem you have confused what to do with ray trace skewing(adding support geo) with artifacts from using a broken cage/simple ray trace value.

jeremiah_bigley wrote: »

Did you use a cage when casting? If not then xnormal automatically breaks the cage where there are smoothing groups resulting in a hard edge bake.

This is pretty much it.

If you bake in Max you won't get these issues by default, and I don't think Maya will give you these issues by default either but its a simple option in the transfer maps thing.

In XNormal you will have to either export a cage from max, or set up a cage in the 3d viewer.

Torch

Hey all, thanks for the replies EQ is right, I’ve confused the ideas here a bit, still have a lot to learn about this process.

I’ve decided it would be a good idea before going the Xnormal route to try using transfer maps in Maya and get good results from that first, but haven’t had a lot of luck with that either – still getting the seams appearing. Are there any options on the TM dialog I should be looking out for to avoid these issues? Thanks in advance – I’ll re-read the thread over my break to see if I’ve missed any info.

Torch

So after a few tries with different methods, I used Sandu's which involved making a cage/offset bake (Geometry/Surface Normals in Maya Transfer Maps) and combined them together to get a clean result. I had to paint out some bits to remove any seams, ideally I'd like to learn a way to do it cleanly by I guess that just takes time. Anyway wanted to say thanks for the help, very much appreciated!

EarthQuake

What was the problem you were having with the "cage" method in Maya?

Generally its a very bad idea to bake twice, combine, or repaint normal maps, because you will have to do it again for any revisions, and if another artist needs to work on your asset he will have to perform the same voodoo magic that you did to get usable results. So its a really bad idea in any sort of professional setting.

You can almost always fix any errors with very simple changes to your mesh. Like if you have a small detail that is skewed, you can cut in one vertex right where that detail is, which softens up the projection normals there and usually fixes it. Simple stuff like that.