Reprojecting UVs?
 

Not sure if this is the right place to ask this. Ive said elsewhere on here that I've been looking at zbrush lately. I made this model and learned a method for creatinga nd exporting a displacement map. Having got back into maya, I set up the render and after a few tweaks ended up with the first image. I had no colour map however, and wanted to try to make one quick as an experiment. I planar mapped the model, but as you can see from the second picture im posting, its messed about with the subdivision of the model. Any ideas of ways around this problem. You can assign more than one set of uvs to a mesh cant u?

and the same model with displacement map still applied, approximation editor e.t.c, but with a newly created set of uvs and colour map...

how is the uv conected to the shader, why did you not let zbrush create the uvs after you created displacement map

I wanted to do the colour map in photoshop. I (is it) a.u.v'ed (?) the uvs in zbrush to do the displacement map, but you dont get something to work with like when you create a map in maya do u?. Am i making sense?

And because my shader had the displacement map applied, which was created from one set of uvs, would it not have messed it up if I applied another map (colour) based on a different uv layout.

ok. Now I'm really confused. It turns out that there was no displacement map at work at all on the above renders. All the work was being done by the approximation editor. Is there anyone who understands the process of creating and taking a displacement map from zbrush and rendering in Maya? I have followed all the resources I have found on this but theres obviously something still going wrong somewhere...

I have only done this once before but if you walk me through what you did mybe I can help, ps could you include a pic from zbrush to see what you are trying to acheive............dave

Hi dave. Thankyou. I have 'Z-Brush Character Creation, Advanced Digital Sculpting' book, by Scott Spencer. In the displacement chapter (chapter 9) he talks about the different types of maps, 16 bit, 32 bit floating point, multiple 32bit maps e.t.c. He reommends 32 bit floating point which I created and exported via the multi displacement 3 plugin for Z-Brush. Then, on the DVD included with the book there is a batch file which you can drag and drop your files onto to convert them. The displacement file was coming out of Z-Brush in TIFF format. What this file does is convert them to .map format via the command line, an automated process and made kind of sense to me as I have heard about mental ray's preference for this file format before...

...deep breath....

So then in maya I set up the approximation editor and the shader. Now on the DVD with the book I mention there is a short tutorial on there covering this process, again by Scott Spencer. However it isnt clear what file format he exports out of Z-Brush but he doesnt convert it to a .map, its still a TIFF, not sure 16 or 32 bit. He also sets up his approximation editor a little differently. He creates one for displacement and one for subdivision. In the book he just uses Subdivision. Plus he uses slightly different settings. On the video he goes for length/distance/angle, in the book he goes with parametric. So there are all these factors which could be at play. Thats all relying on the fact that I created a successful displacement map in the first place. Again, I did this by following the books instruction so Im assuming I have. I have tried several variations of the above settings, different approximation settings and values.

This is the picture of the ztool I generated the map from. This is at level 6 or 5. I generated the map off of level 1. And it is the exported level 1 obj I am trying to put the exported map back on in maya.

...deep

p.s, i didnt mean to complicate things by using a different model from the previous pictures.


...so I guess the map must be doing something in creating those wierd artifacts. So im guessing the problem is with the map rather than the maya set up. I know about flipping the map in the v-direction, I checked the option to do this in the z-brush export options so as far as I know it has been flipped. As I understood it aswell, when using a 32 bit floating point displacement file, scaling wasnt an issue either. I have read there are maybe some option sto constrain the scaling and proportions when exporting OBJ's from z_brush, but I just exported straight from the tool menu, understanding scaling shouldnt be an issue. HHmmm, maybe that something I should check.

This is all im getting so far...

the picture you supplied from zbrush looks nothing like the one you first posted is that correct? or are you trying to get the first post effect?........dave

ps. yes there are some things you must do if you want to change the scale, if you have change the scale of the model this is most likely your problem.........dave

yes it is a different model. Having the same issues with both.Im not really rescaling it though. On import in maya I am just leaving it as is.

well. I dont think this looks right. This is the 16 bit map in photoshop, the 32 bit one looks exactly the same but with less contrast

hmmmm

ben will get back to you tomorrow, having a drink,
that is what it should look like.

I may have found the answer!!!!!!!!!!!!!!!!!:attn:

The problem seems to have been with the settings in the displacement exporter in Z-Brush. I was reading about the differenc between 16 and 32 bit maps, and where id tried the 16 bit type first of all, when I then switched to 32bit, the 16 bit type was still checked to on. So I was creating two maps at once which I guess were messing each other up.

As for the grid like look of the map above. A guy on zcentral said thats what it should look like too. I know that when you create uv maps in zbrush they do have that broken up tiled look, but actually the displacement map Ive had success with looks a lot more like what it represents. In the tutorial video I watched aswell, the displacemnet map for a character, when opened in photoshop, looks recognisably character like, you can see the eyes mouth nose etc. I wanted to post up a picture of what my displacement map looked like, but opening Tiff's in photoshop, i cant save out as a jpeg. But this next picture is the result I got in Maya, and the map for it looked like a load of squiggly lines with arrow heads, not the grid type thing above???

with alpha gain increased and alpha offset adjusted...

...I just hope now I have found some settings that work, and will get similar success on a something 'real' rather than just this quick experiment..

Ben there are other ways to do uvs in zbrush see link bellow

http://www.3dlinks.com/oldsite/tutor.../Tutorial6.cfm

Thanks for the link dave. I had another couple of successful displacement exports, and think im getting the hang of knowing which settings to adjust when things arent going as smoothly as I plan.

I wonder, u said uve created displacement in zbrush and rendered in maya. i was curious, was z brush just a passing thing for you? Or do u now just use other methods? Im looking for some guidance on a practical workflow. I have this model which id like to sculpt in zbrush. Base mesh done in maya. Im not keen on what ive experimented with zapp link and not a huge fan of polypainting, so id like to use photoshop for texturing. Im a bit confused about what the best workflow for such a process is.

Hi Ben
I am a intermedate Zbrush user still learning. the only reason I said use zbrush uvs is one of the tutorials for displacement map said the uvs created after the disp map will take into accout the disp map. I need to look into this also as I will be doing some thing along those line with the Birdman WIP.
Maps created in zbrush can be used in maya and textured in photoshop..............dave

It sounds as if we're on a similar track. I'd be interested to hear how u get on. Im a bit confused because the only two ways i know of creating maps in zbrush so far, are group uving and Auv ing, is that a standing for adaptive(?) not too sure, but Ive not seen a useful map come out of zbrush in any tutorial I have seen yet. I hope you are right as from my limited understanding so far, if you uv map everything in maya first then the base level object is going to change anyway once youve done some sculpting, so I think maybe you sculpt, then export the base level objs, uv map, then re-import to z for the displacement map creation. But then.....sigh,...

I havnt looked at the link you sent me yet, ive had two long days at work. It was great last week I had a week off and really thought id made some progress. But off again for the next two days so looking to get stuck back in. Im asking questions on zcentral also, do u post there?

Hi Ben
Dont let zbrush confuse you, zbrush generates maps in a funny way, the displacement map you have created is not a uv map but a displacement map. if you create a uv map in zbrush it will show up in the texture box, if you create a bump map it will show up in the alpha box. Dont try to learn to much at once as you will go around in circles.
If you createuv map in maya import it into zbrush with your model.

No I have not posted t zbrush.................dave

quick polypaint. Ive already exported a displacement map on this so Im going to see if I can get this colour info to texture.

more grid like artifacts..:confused:

turn off render visibility on your hrdi

do u mean 'primary visibilty' in the render stats for the image based lighting? I will have a go.

if that is what u meant i had a go, but its not affected the tearing. I thought it was doing that before i put the ibl on, but I thought i'd quickly double check. I think the problem lies in the displacement map and/or the settings in the shader/approximation node. I dont really know.

:shakehead

Its the render settings. If i adjust the mental ray settings (production), the subdiv approxnode(length distance angle, view dependent, length 0.1) and the displace approx node (length distance angle, length 0.25, view dependent) I start to get a nice artifact/seamless render.

alas, after 20 minutes or so, my computer folds on me...

....


..... Dear Santa, ....


....e.t.c....

sorry it was just distracting. i didn't think it would help your disp map... I'm no expert on zbrush the only thing i know is that zbrush has a funny 0 and that you have to do some kind of sum when you are using maya. I can't quite remember, sorry. Looks like you are all set anyway.

yeah, one of maya's / zbrush's idea of o is mid grey and the other is black? Cant remember off the top of my head which is which. Had those settings covered with the alpha gain and alpha offset sliders.

its a crappy model with crappy textures, but still, a shame to learn that my computer isnt going to render displacement. Its no big deal I guess, I don't have a pressing need really to create them. Just hoping to try and recreate some of the gorgeous renders I see of zbrush models.:shakehead


....if only...

Hi Ben
dont give up yet, have you got your render setting to draft (you can set this to custom at a later date), set your subdiv approxnode to parametric at 3 to start with then increase as needed.........dave

ps. I am on a P4 3.2 ith 2GIG of ram

some of what I have done

Im not giving up. But I was thinking about what u said about trying to learn too much too fast and I think you're right. I have really thrown myself in at the deep end with zbrush and been trying to cram learn. I need to be more patient.

your maya modelling is good. and the forms are coming on in zbrush, particularly the skull

Sorry Ben I should have explained, the modelling for that model is finished, he is going to wear a coat so i will not model his chest, still a lot of work to do.....dave

ah, a soldier of the undead...?

I was working on this character. But after an hour or so of work, i went to load him up in zbrush to carry on (this was about a week ago) and zbrush just kept crashing. Dont know why. But this is an image I got at the end of the first session.

Didnt you have a problem with poly count in zbrush, may be you have to change the settings again to bring a high poly count item in?

But I hadnt uved him, so I knew it was a bit of a non-starter anyway. Today I uved just his hat (im not very experienced with uv-ing) to try an experiment. I wasnt sure if you could both texture in photoshop and polypaint, kind of simultaneously. But I realised today you can, so I guess my next step is to uv the rest of the character and keep my fingers crossed z brush accepts him next time. Think I feel some modern warfare 2 coming on.

yeah. I had had some problems when i was trying to go from level 5 to level 6 on a couple of the subtools. Really elongated waiting time between strokes and visible outcome, and sometimes just plain failing to up the level. But as I hadnt uv'd him I knew, like I say, it was a bit of a non-starter. I was still wondering about colour maps, and the whole uvlayout thing so it was almost 'a sign' I guess, that I ran into trouble. It also gave me the chance to add some more edge loops in maya, as some of the geometry was very light and struggling to take much/any detail at the mid-subdivision levels.

Totally unrelated to the point of your thread (but your model is looking good so far!) but I was just wondering if we've ever done battle online, you on Xbox or PS3?

ps3. I go under the name 'cambodgienne'. There are a couple of pictures in my room by a famous french artist, I cant remember off the top of my head by who, one is a sketch of a dancer called 'la cambodgienne', i thought it would be easy to remember...