Extracting normal maps from very high poly models in ZBRUSH?

melviso · Mar 2012

Been using ZBrush for a while now for high poly models with no uvs.So since ZB can handle very high polys compared to other apps I was wondering if there is a way u can select the high poly model,the low poly uvied one and extrct the normal and AO maps for the low poly.I can't find it even in Multimap extractor.I am guessing the only way is to project the details of the high poly mesh to the lowpoly after subdividing it to a level that it can take the details of the high poly and then go to the lowest level and extract from highest subdivision level of the reprojected low poly.I hope this isn't the only way as Mudbox even has this feature I speak of.

I don't want to use decimation master as I might lose some details.I tried exporting it without decimating into xnormal and it said out of memory or something like that.Maybe I would try it again.

Ace-Angel · Mar 2012

ZB cannot bake from High to Low, what you must do is bring in a low-poly (with correct topology, etc) and have that be your new mesh. Basically, divide your low till you have a good amount, and then project the high from there so it becomes your new high mesh.

You then bake from there.

Mudbox is a different beast since it was designed from the get-go as a full traditional workflow concept (unlike ZB which started like a 2D app), so take it for what you will.

Also, decimation master shouldn't be killing ANY of your details? Could you post an image of what you mean?

Try aiming for around 500K, also, remember that ZB doesn't smooth out the your details, it never did, if you zoom in, even at 4 million you will see the unsmoothed details. So yeah, what make look as a 'loss of detail' is actually ZB showing it's true colors, in any other app, it should look fine.

For xNormal, 64 bit is recommended, but even in 32 bit, it shouldn't run out of memory for baking. Try increasing/decreasing the bucket size, and don't use any AA.

SpeCter · Mar 2012

Ace-Angel wrote: »

ZB cannot bake from High to Low.

You´ve got to be kidding right?

cryrid · Mar 2012

It bakes from a higher subdivision down to a lower subdivision, but it wont bake from one mesh/tool to a new one.

passerby · Mar 2012

ya olny between subdiv levels, what i think would be amazing if the xnormal and zbrush people got together for some really tight integration between the 2 apps.

melviso · Mar 2012

@Ace-angel
You are kidding right?With all the powerful capabilities of the great ZB,it lacks one of the most important yet simple feature for sculpting apps?Why do they do that?Is it that the devs of ZBrush can't add this feature or what?I am beginning to get fed up with apps that are really cool but lack some simple things they should have had from the first release,so one has to look for another app to carry out such tasks.I guess I will use the decimation master and xnormal then.Thanks .

@SpeCter
I can't beliveth it either.

@cryrid
I am hoping at some point they add it but maybe they feel they shouldn't be bothered since xnormal does the job of baking for its users pretty well.

SpeCter · Mar 2012

I know it can´t bake to different tools, but he let it sound like zbrush isn´t able to bake high to low at all.
All it takes is importing a clean uv´ed lowpoly recreating higher subdivisions and bake then
.

cryrid · Mar 2012

I'm pretty sure they used to have a similar feature within the old zmapper plugin, including an ogl viewport for previewing the result, but that was removed ages ago (around 3.5ish). I think the issue isn't so much that it's missing an important feature, but rather it can and does bake normal maps... just not with the workflow that a low-poly artist might crave. It's probably along the same lines where it doesn't use standard materials or even draw polygons in the same way a standard 3d application does. It's powerful because it focuses on the sculpting, and not on the complete tailored workflow for a specific portion of the entire userbase.

Personally, I don't mind. If I have a sculpt obj and I have a low poly mesh obj, loading them in xnormal isn't going to take any additional effort. It's also going to give me a lot more options for baking maps, and more control when it comes to things such as setting up a projection cage or choosing the tangent basis I want to work with.

Ace-Angel · Mar 2012

Uh, guys, did you read the rest of what I wrote? I specifically said:

A) You need to re-project the high detail as MESH to the new MESH since ZB is not traditional and doesn't bake High to Low separate mesh, need new mesh to replace old mesh.

ZB started out as a 2D hybrid App before making the 3D leap, even now it's not proper 3D.

I didn't any of the extra info for my own health you know *coughcough*.

cryrid · Mar 2012

Uh, guys, did you read the rest of what I wrote? I specifically said:

I'm talking to Melviso, not correcting you.

melviso · Mar 2012

Ace-Angel wrote: »

Uh, guys, did you read the rest of what I wrote? I specifically said:

I understood what u wrote.I am just a little surprised that it does not have that workflow like in Mudbox or other sculpting apps and its very powerful.I was guessing it was hidden somewhere in ZB's complex and infamous UI.Thanks for replying,Ace.

@cryrid

I agree.Its not really much work to use xnormal.I will just study on how to use the decimation master to get the best out of my highres model.

Thanks for the replies,everyone.Now,gat to go back to ZBrushing.

melviso · Mar 2012

Xnormal seems fair but I kept getting this window alert that :''The high poly model radius is less than two units (2.0), please scale it a bit up if you get bad results''.
I have been getting very bad normal and ao maps.Then I had to import the very heavy high poly model into Maya(assuming u can't scale meshes in ZBrush using numbers as it lacks a real 3d world) and increased the scale to 4 and did the same for the lowpoly model.Imported back to xnormal and the normal map came out looking okay,the ao map had some black patches.Any way to get very clean,more precise maps and also is there a way I can increase the scale in xnormal without importing meashes into 3d app for scaling?

The model looks very good with the hardware renderers but sucks with the Maya software and mental ray renderers.Why is that?

passerby · Mar 2012

try using the xnormal viewer bit to make a cage. and iirc there is a scale option in xnormal.

EarthQuake · Mar 2012

It would help to post some shots of your models, the maps you're getting of of xnormal, etc etc.

Goeddy · Mar 2012

i suppose the black patches are points where your cage isnt set up properly, so the maps cant be projected correctly.
i recommend setting up the cage in an external software, like max or maya, for full controll.

if you want cleaner maps increase the ray-count for AO´s and the mapsize for normals. then scale the normal down to the desired resolution.

i do all the baking in max cause it shows you very clearly were your maps dont project properly, so you can adjust the cage perfectly.

also get used to switching applications frequently, cause there is always one, that does a certain task way better then all the other ones.
having a good folderstructure minimizes the caused delay.

Pivot · Mar 2012

melviso wrote: »

also is there a way I can increase the scale in xnormal without importing meashes into 3d app for scaling?

You can change the scale in zbrush. There's an Export tab at the bottom of the Tool menu where you can increase the scale. You want to make sure the number stays consistent between your high and low poly.

Popeye9 · Mar 2012

you can change the scale of the export in zbrush by going to the export section under the tool tab. Here is a picture of what I am talking about.

melviso · Mar 2012

@passerby
Thanks a lot,..I increased the scale of both the low and high poly mesh to like 100 in xnormal and the error window did not come up.Rendered out my normal and ao maps.

@EarthQuake
No worries.The renderers work well with the maps now.I just had to reverse the normals on the model.Mental ray does seem to be displaying some wierd stuffs though while the hardware renderers displays everything correctly.

@Goeddy

I am not gonna lie here.I hate the 3d viewer of xnormal,the view sorts of lags,camera navigation wierd,the UI thingy is confusing and I can't even comprehend moving vertices of a cage in it.I know of someone who uses Maya for baking normal maps,says mental ray baking gives way better results and u can manipulate the cage.The only thing that might be a problem is viewport lag as a result of the high poly mesh.I remember using Mudbox for my 3d works then.I used it for extracting normal and ao maps and they turned out awesome.What I love about MB maps is how well they render with mental ray and I never had to modify a cage to get good results.The only problem is the huge file size MB becomes when moderate work is saved in comparison to ZB.Xnormal seems to work more for hardware renderers or viewport renders.

I am one of those people who don't enjoy moving for one app to another as it encourages creating files all over the place to export stuff.I also like orderliness and a straight forward workflow.Too many apps,kinda create confusion and disorder especially when with files saved all over the place and in specific formats.I kinda miss Mudbox though.All I used before were:

Maya-base modeling,uvmapping;Mudbox-detailing,baking,reimporting uvied low res model,load in baked normal and ao maps and painting all textures I need.Topogun-retopology/creating mesh like cloths,hair e.t.c.
-The only backdrop to this workflow is speed.Maya modeling tools isn't built for speed modeling.

Now I use or trying to get used to this:
ZBrush-freeform modeling/sculpting,retopology;Maya-uvmapping & baking cage modifications;Xnormal-baking normal and ao maps;Zbrush-polypaint diffuse map on high poly;Xnormal-bake diffuse map;Photoshop-paint more details and make other maps.
-with zbrush,one can create models fast,but the movement from one app to the other is frustrating.

@Popeye9 & Pivot
Thanks for the heads up,did not know there was some options lurking behind the Import and export pallete in Tools.Thats what happens when u have a UI like that in ZBrush.

Extracting normal maps from very high poly models in ZBRUSH?

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