Why my normal gets so bad ?

NAIMA

Hi I just did this simple thing in Zbrush to experiment with normalmap extraction etc ... now I get this weird texture normal ... I have overlayed to show up better the uvmap , but you can see all those more bright linees and such stuff that is not present in the model ...








Now I just went on the normal map tab and clicked generate normal map , then it says to put to lower subdivision so I put all to 1 subdivision and then I create the maps and clone to texture map and then export but that's the result ...

why ?

expecially noticeable the vertical bands and the fact thet the riveds on the frontal tip got sliced ...

cryrid

Do you have any UV coordinates touching the boundries (0:1)? That tends to cause such errors in zbrush. If so scale the UVs in a bit and rebake.

NAIMA

this is the uvmap :
notice how the rivets got cut away and how those bands rise , not saying that the whole normal map is uspide down compared to the original uvmapping...

cryrid

The bottom island (strap?) and whatever is in the top-right appear to exceed the 0:1 border.

'UVs should not extend right to the borders of a UV space but be scaled down a little
inside. UVs that are on a border may be assigned to the wrong map or cause overlapping
issues.'

NAIMA

so I need to redo the whole thing or I can reuvmap and reimport as base model? without loosing all the done stuff?

cryrid

Yup, you can just redo the UVs.

NAIMA

i SET THe subtools to 1 subdivision and imported the newly uvmapped obj , for the circlet no problem , for the plaquering no problem but the frontal nose protection gets screwed up all the time and I dunno why ....

Docm30

Maybe I missed something, but if you are just changing the UV on the low-poly model, why not just use the old high-poly to bake the normal-map from?

NAIMA

I woul dneed to export out and bake over a low poly to do this no? Instead if the model already has good uvs I do not need to ... I guess....

cryrid

I think the model's information must have changed somewhere between exporting and reimporting for that to happen (looks like it is trying to accommodate for a change in topology, not just a change in UVs)

I woul dneed to export out and bake over a low poly to do this no? Instead if the model already has good uvs I do not need to ... I guess....

Sort of. If you're doing it entirely in zbrush, it's just using the lowest subdivision for the low-poly and the highest subdivision level for the high poly. So it would be like exporting both and using them in another app for the bake instead.

NAIMA

I modeled the low poly in 3dsmax , uvmapped there imported in zbrush , sculpted there and since the models did have the uvs I created there the normals , but the problem is after I fixed thanks to your tip on the textures, how can I control the strenght of the normals? how I can prevent to flip and also why when I apply them in 3dsmax they look upverted in render and almoust few strenght?

What's the best workflow tough to extract normal maps from a high poly model made in zbrush?

Pola

I'm having difficulty understanding your english a bit. More pictures with some circles/arrows might help. I think it might be possible that your low poly needs supporting edge loops, something to do with normals and polygons that have sudden angle changes, you can read up about all this on the polycount wiki.

Try exporting the high from zbrush and baking to the low with the fixed uv's in xNormal.

pior

Don't bother with normalmaps in Zbrush - that's not what it's made for.
Simply do the following :

- Export your high from Zbrush to OBJ. If necessary, decimate it using Decimation Master.
- Import it in Max.
- Build your lowpoly in max, give it UVs.
- Bake in Max.

NAIMA

I have xnormal , topogun and of course 3dsmax , they are all better than the normals from zbrush ? wich of the tree is the best option? I already have the low poly as I made it on purpouse to sculpt it on zbrush but also use it after ....

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cryrid

I have xnormal , topogun and of course 3dsmax , they are all better than the normals from zbrush ?

XNormal and 3DSMax should both give you more control over the result than zbrush. Plus with zbrush it is harder to transfer the detail from a sculpt to a mesh with different topology than the lowest subdivision level.

There should be plenty of tutorials for using both to create normal maps.

NAIMA

cryrid wrote: »

XNormal and 3DSMax should both give you more control over the result than zbrush. Plus with zbrush it is harder to transfer the detail from a sculpt to a mesh with different topology than the lowest subdivision level.

There should be plenty of tutorials for using both to create normal maps.

Thanks a lot that makes more clear ... I could fix all problems in normal map indeed and they where due to the things you said , as for the worflow I will give a second try to xnormal that I left couse it gived bad results as he ones I had in zbrush , So I guess now they may be due to the same cause ....

Ace-Angel

You can't use the Normal Map from ZB correctly since there are many issues with them.

For example, they don't match many tangents in many engines or packages, too deep a detail doesn't get captured correctly and will appear black (which should not be the case EVER) and you don't have control over cages and such.

xNormal, Max, Maya, they are all better solutions.

Also, I have to voice what Teriyaki said, try out stuff, there is no point in someone telling you something if you don't plan on trying said stuff first before posting up follow questions.

NAIMA

Thanks but I did try all what was sugested ...

Pola

If your still getting baking issues, it could be either your uv unwrap or your cage might need tweaking. Did you try adding support edgeloops to the low poly to see if that improved the bake?(Might require uv tweaking afterwards).

NAIMA

I am not having baking issues so far after I fixed the UV in zbrush , the only issue is that the normal maps , that looks fine loaded in xnormal , in 3dsmax looks inverted so the bumps are cavities instead ... I am going to redo the surface detail of the model for some minor issues I got ... but unrelated to the normal map extraction , I just wanted to know touch wich one is the best method for a workflow , if either zbrush max , or xnormal ...

mystichobo

NAIMA wrote: »

in 3dsmax looks inverted so the bumps are cavities instead ...

flip the green channel.

Pola

The best method is whatever works best for you :P If you tried them you should have a fair idea which one works best for you. I like xNormal because of its speed and flexibility. You can also tell it to flip the channel when baking, you'll find different apps bake or read the information differently. So like mystichobo said, just flip the channel Can do this when baking or in photoshop, open the normal map go to the green channel and ctrl+i.