GUV tiles vs. AUV tiles in use of UV space

[system]

I’ve seen this question raised a few times in these forums, but I wasn’t able to find an answer. I’m trying to map an imported LW model of an aircraft for texturing in ZB. I’d like to use GUV tiles to create a texture with the least amount of distortion, however AUV tiles make much better use of the texture space. See the attached images for an example.

I imported the model in question, created a texture at 4096x4096, set AUVRatio to 30, and hit GUV or AUV tiles button. If I have to, I’ll just take a swing at the texture using the AUV tiles, but I’d really like to see the GUV tiles make better use of the space. Is there a way to better optimize the GUV tiles? I suppose I could move and resize the tiles in LW and then bring the model back into ZB for texturing, but that seems awfully tedious.

Attachments

[aurick]

It seems that the most efficient use of texture space is normally accomplished on the GUVTiles by leaving the ratio at 1. Also, if you are going to be doing displacement mapping, you should ALWAYS leave the ratio at 1 in order to avoid rendering seams caused by disparities in pixel interpolation.

[system]

Yeah, I noticed that the lower ratio helped, but I’m trying to use text and fine details in my texture that become fuzzy when all of the UV’s are consistently sized. Perhaps I need to map parts of the model to different maps rather than trying to cram all polys into one map. I could map the fuselage, wings, and engines to seperate maps, but each of these maps would have the same problem as the map that prompted this post.

I don’t plan on using displacement on this model, so that’s not really an issue. I just need to be able to put fine (not fuzzy) details into this texture. I’ve seen plenty of models in the galleries with nice detailed textures. How are you kids doing it?

[epiginosis]

I would highly recommend you unwrap your model in LW before importing into Zbrush. I have gotten finest results this way in that smaller details are projected onto the model much cleaner.

[system]

epiginosis, how do you generally map your models? Are you just using the atlas projection and then importing to ZB? I guess I could see the logic in that. All polys would retain their respective sizes, and I supppose there would be no distortion. However, if your talking about manually unwrapping the model to get a nice continuous “skin,” well that’s exactly the kind of tedium I’m trying to avoid.

Please share a little more about your workflow. Also, what kinds of models are you making in LW and texturing in ZB? I’d love to see examples. This is my first full week with ZB so your help is most appreciated.

[epiginosis]

Unfortunately my technique does add an hour or so to the texturing process. And unfortunately it may take someone not familiar with the LW texture guide tool and unwrapping even longer.

FORTUNATELY!! The process of unwrapping in LW does save time in the long run with ZB because projection master will project fewer mistakes and unwanted do dads onto your texture in the texture pallette. Plus, if you do want to fix, change or touch up your texture later you can do it with ease by eliminating the guess work found in GUV and AUV tiles projections. To further explain, projection master doesn’t always give you a clean projection, especially with lower poly objects and objects with a lot of triangles in it. So you sometimes have to paint directly on the 2D texture by using the Grabber tool in ZB or Photoshop. GUV has a grouping kind of pattern it uses but it still isn’t as simple to correct mistakes as painting on a texture that has been mapped manually.

I can tell you that mapping a vehicle or aircraft would be a relatively easy thing to unwrap and yes atlas mapping may work nicely. However I do a lot of character work for games and so I need to use traditional mapping techniques to effectively use up texture space. I just appreciate the control over the UV’s and where the texture is projected onto the texture doc. For hi res/poly film objects or stuff for illustration, texture space may not be as important to you and so Atlas or GUV tiles may work fine when using projection master with a dense polygonal object. Using GUV with a model that has a million polygons in it may give you the results that you want. I’m mostly speaking in animation and game terms using medium to low poly objects which are necessary for a complex animation scene without having to rely on standin models for animating. Plus a medium resolution model doesn’t take as long as a dense model to render. It’s all a matter of how much time you want to put into your project.

Don’t take my word for it, test different techniques and find out which work flow is fastest and produces the best quality for you. Let me know if you want to learn more about what my workflow is. I’m glad to help.

[system]

Now this brings me to a question… if you go to the trouble of unwrapping your model manuallly in LightWave, why even bother texturing with ZB? Wouldn’t it be easier to just use PhotoShop at that point since you already have your UVs as you want them? This is the way I’m accustomed to working and it can be time consuming. Unwrapping a medium to high-res model of an aircraft is never fun. I’ve been doing it for a while like this, which is why I’m always looking for a better/faster way.

I think you’ve given me some solid advice and a few good directions in which to move. I need to try a few different approaches and see what works best. GUV tiles may not be the savior I thought it would be, but I think ZB will still become an integral part of my workflow (that is after I stop playing with all the fun stuff).

[epiginosis]

Well, even though I unwrap and go through all the trouble of putting the UV’s exactly where I want them, Zbrush does a number of things automatically for me that I would have to do manually using just Photoshop and LW.

1. Zbrush eliminates all the seams.
2. I no longer have to fine tune the UV cords to match my painted texture even though I still have to minimize the stretching of the UV’s using a checker or stipe texture as a guide in LW. Minimizing stretching and (I don’t have to perfect it) ensures that Projection Master won’t give me speckles or splotches when I hit the Pickup button.
3. I no longer have to jump back and forth between PS and LW and update the texture to see how my texture is being projected. HUGE time saver. Eliminates guess work. I get a realtime render every time I hit the pick up button in PM.
4. GUV tiles seems to be very dependant upon texture resolution and the poly count of the model which may cause unwanted distortions jagged edges in your brush strokes. This means you have to fiddle around with the settings in ZB to get the desired results. Therefore you’re using more time adjusting the settings and not necessarily getting those fine details that you want. Using time more effectively by correct UV unwrapping can eliminate all those problems through manual control and guarantee the desired results at any poly count and at any resolution. The UV maps are exported with the model using the Obj exporter that comes with LW and many other animation packages.
5. In ZB I have a number of bushes and other tools to give me a wider range of texturing effects that just aren’t as precise and practical to do with photoshop. Namely the ability to paint a pregenerated seamless rock texture and add little plants and moss on it using the alpha channels/ stencils and Texture pallette with PM. This can be done with any character or vehicle too by painting bullet holes, scratches, bumps logos etc. Plus you can paint bump maps and see how they look in ZB before export. It’s just faster than bouncing back and forth between apps and adjusting UV’s and painting effects. I get a real time render every time I paint. More texturing power to everyone!!

Hope this helps!