Need help with Xnormal backing

NAIMA

Hello , I am trying to bake a normal map in Xnormal ...
this is the process I am doing ...

I modeled my high poly version , then retopologized a new model over it with topogun , imported in 3dsmax , fixed all seams arranged the textures and uvmaps on a doubled side area along the X axis so to have adaptation to a texture sized as 4096 x 2048 in x y ....

now when I exporet the model I restretch the texture uv to a single quad so that the OBJ has the coordinates on a single quad .. .in Xnormal then I recreate the correct proportions for the textures ...

all seems coming fine apart from some internal portions of the mesh baking ... as you can see in this picture there are strange artefacts and weird stretching I dunno where they coudl come from because as you can see in the sidened image all is finely even in checker pattern ...

what do you think coudl be the problem and how coudl I fix?

thanks for any kind answer ...



Hi if anyone is kind enough to give a try at this download coudl perhaps tell me whats wrong in the backing process?

I uploade high and low poly ....

http://www.sendspace.com/file/bo7csd

Hang10

My opinion is that this is the result of stretching your texture multiple times.

If you plan on having your texture sheet rectangular then you shouldn't have to re-size it during the baking process. xNormals let you bake with files that aren't squared.

respawnrt

I don't know, could be a lot of sources for your problem.I always use uvw xform for textures that aren't square(use the 0.5 scale), i just put it in the modifiers list in max and mind my own business.and also i don't collapse the stack.
Did you exported a cage for xnormal ? Did you checked with smaller checkers for distorsion ?

NAIMA

mm mnot sure I understand your sugestions ...

I have collapsed all I have stretched the uvmap in 3dsmax to stay inside the even sided square .. while it actually is perfectly cheker aligned when it covers two squares in horizontal lenght ..

when in xnormal I create then the map stretched as is needed ...

The problem is that I used that technique a lot and never had those problems I suspect it coudl rely on somehow overcrossing projection due to the fact that the highpooly model has a outside and an inside part ( its like a gown ) and so is also the lowpoly model that follows the shape of the highpoly ( As I did it in topogun ) .

Hang10

Just so I understand your exporting the mesh with UVs that fill the 0 to 1 space, but in xNormals you rendering a 4096x2048 map?

NAIMA

yes all the other sides of the texture look fine , I tested by reducing the maximum frontal ray distance and I got more of the same type of artefacts....

I then tried to increase to 2.5 from the previous 1 but I still get the same results increasing I cant get rid of decreasig I get more ... any other ideas ?

NAIMA

I could fix sligtly by redoing manually a bit the modeling and not using topogun but now I wanted to know if is possible to import inside topogun not the reference but the actual low poly model ?and Multiple reference models to make a single one?

Farfarer

What's the ray distance inside xNormal? Have you tried resetting the mesh's normals before exporting? Could be a vnormal/cage issue.

NAIMA

what you mean by resetting the mesh normals ? how shoudl I do it in 3dsmax or xnormal?

in Xnormal I started by 0.5 , tried then from 0.25 up to 2.25 ...

I remade also the interior portion of the gown , the one that gives the problems , I redid exactly like is the lowest sub level of zbrush , exported from zbrush the portion imported in max replaced the interior face mesh of the gown there with that one , relinked all and merged into the single mesh , then I exported to topogun and fixed any other problem , topogun results in a very smooth and conformed surface to the interior part of the gown , so no problem is seeable ... but when I export I still get the same damn problem even after all this work ...

if one is interested I could send the model and see if can help me with that to understand what coudl be?

NAIMA

Here is a picture ofthe model inside Xnormal ...



from left to right

both high and low poly model in place
low poly model only
the problem visible in interior parts of the gown ...


Apart the previously exposed questions on this problem ...

how can I do also to increase the Depth of the normal maps to look more like the ones in the high model?

NAIMA

Here a picture of the unexpicable problem in backing as you can see a piece of the border comes into the normal map texture on the inside , but its far and I have no idea how can get to there ...

NAIMA

OK I have tried to use a cage , but this gived really bad bad results decuplicating those kind of errors ... I am out of ideas now -_- ...

NAIMA

Hi if anyone is kind enough to give a try at this download coudl perhaps tell me whats wrong in the backing process?

I uploade high and low poly ....

http://www.sendspace.com/file/bo7csd

Boyso

I get artefacts in the inside too, but does the exterior look better?

Ruz

why not just bake the front and back separately 'or' don't bake the inside, just duplicate the outside and flip it.

Boyso

Well I kinda agree, with legs in there and AO, I doubt it'd be noticable.

NAIMA

Yes I know I coudl even handpaint the error but , why I get this error is my point , I also get other small artefacts on frontal lower borders ... this is really weird and I would like to nail it down possibly as it's annoying that I can't get it to work , also I can't bake in 3dsmax as my pc can't handle that model to be loaded in 3dsmax it would just crash my pc ....

What can I do to fix?

Ace-Angel

Did you clean the mesh before exporting it in SBM format with a cage? (Reset XForm, Pivot, Edit Poly Modifier and Collapse it, etc)? Also, don't forget to select all vertices and weld them at a low threshold, same with UV's.

Same for the high poly (although the HP shouldn't matter too much if it's a simple sculpt).

Because if you're getting errors with a cage, in Xnormal, then there is a problem with your mesh, and big one one too, try to reset and clean everything possible before exporting, because again, a cage shouldn't be giving your errors at all, never, especially like that.

NAIMA

did you try the file?

I haven't done reset Xform , pivot , edit poly modifier I just add this to the stack select pivot and collapse?

Wonkey

I just tracked down an issue I was having, that looks like it might be similar.

In max, go to element mode of the edit/editable poly and hit unhide all. I suspect it might be that one of your high polys is hiding something.

dtschultz

Yeah, this drives me crazy with Xnormal. I haven't been able to figure out a hard and fast way to fix this kind of problem. A lot of times importing a cage fixes it, but if not the only other way I know is to separate out the objects e faces that are getting projected onto each other. I've also just taken the object into Max and baked it there (I've had some objects that curved back in on themselves I just couldn't get right).

Definitely post your solution if you find something better.

dtschultz

At the same time, I'm not a character artist, and this might not be acceptable, but why can't you just use the same normals from the front of the cloth and the invert the appropriate channel? If you mirror it at an appropriate seam on the cloth it shouldn't be a problem, right? Or am I wrong?

Froyok

I tired to to open your low poly file in maya to check your geometry but there is an error (" OBJ file line 8627: index out of range for face creation."). Can you export an fbx file ?

Also I think you have an ngon of an UV problem, because in Marmoset I get a strange face artefact :

Ruz

well it seems to me that somewhere when you saved out the low poly obj it got corrupted, as some of the polys are black. So i exported it out of max then re imported which fixed that. I then decimated your HP in zbrush as it was absolutely huge - how many millions of polys is that LOL.( nice model though)

anyway did a test bake in max on default settings with no cage and it looked like this



looks ok for an initial bake I suppose.

max file is here, should work ok in xnormal too

http://www.mikerusby.com/images/chainmail/chainmail_bake.rar



xnormal bake - not perfect but minus the artefacts you mentioned.

NAIMA

hello , thanks all for ur kind answers and time ... by now I have sliglty chaned the model , but I didn't get the black face thingy ... so also in marmosed I could get them to look fine as this is the result ...



But

I still get those above mentioned artefacts , I just fixed by hands ....

but on the red areas , where I actually shoudl have added some detail berders and over armor parts I didn't yet couse I get crossface projection resulting so in normals and occlusion with parts of the chainmail over areas that shoudl be either leather or metal .. .I have tried to reduce the backfacing ray distance to 0 but this increased the problems .. .how can I do to improve ?

and Ruz how u did manage to get a better xnormal bake?

NAIMA

so there is no solution for that problem with xnormal apart going back later with photoshop?