A New Tutorial, Some New PS Tools, and Some Questions

[madart]

Excellent stuff! Will get back to you when I have checked this out. :)

[EricChadwick]

Kevin, thanks for these. Great stuff!
On p.30 of the PDF you said "DXT1 can exist compressed on-GPU"
But DXT2-5 cannot? I thought all five were able to remain compressed. I must admit I'm still a bit hazy about graphics memory. Are you talking here about texture cache or video RAM?

p. 45 "smudge and gaussianblur"
I made a Photoshop Action that simplifies this. Also lets us use better sampling on irregular charts than just point, since I can smudge all those tiny edges in one go. I've been sharing it online, you can have it/mod it/share it if you like.
http://www.ericchadwick.com/examples/files/uv_edge_filter.zip
It basically takes the edge pixels of each UV chunk and expands them outwards, into the empty space between the chunks. Could be modified to blur them too, for less "streakiness".

P.43 "So use decal coordinates, if they are valid & monotonic"
I'm not sure what you mean by "decal coords." Are these the model's existing coordinates that the artist created? I looked it up in the Melody User Guide, found no details there.
Also what do you mean by "monotonic?" Do you mean the UV chunks specify equal texel sizes on the surface? The head on the next page is not equal-area, the back of the head is smaller on the atlas than his face, but you call it monotonic. I guess you mean something different.

pp. 59-65 "Common Problem: MIPS gone bad…"
On p65 the middle pic is the desired result, but you didn't show what map will get us there. I guess to avoid the problem we want to create a set of MIPs with a frequency somewhere between the original set and the procedural set?

Thanks again, great paper. I have yet to try out the tools, but will let you know how it goes when I do.

[bjorke]

DXT1 is compressed IN THE CACHE not overall. But that can mean a real speedup.

I'll have to try that out -- there's also an image-dilation example in the latest (9.5) version of the NVIDIA SDK that can perform this in real time on moving images (or read a texture into the background and it will do it to your painted pic).

Yes, decal coordinates mean artist-generated UVs. By "monotonic," I mean no folds, so that no UV location is repeated in different places on the same model (or multiple times on the same spot!)

To get the middle image would require tuning the MIP levels -- whether by color-fade or hand-tweaking. That's the rub -- there's no single solution, sometimes you just have to take the model and zoom in and out on it and decide if it looks okay or not. The world is full of so many different kinds of materials, our algorithms only really can display a small fraction of them.

[EricChadwick]

Thanks for the reply. I'm still hazy on the DXT cache, but it's probably simpler if I just ask a coder here to lay it all out for me.

About favorite Photoshop tools, I often make Actions for my repetitive tasks. FWIW here's a screengrab of my Actions palette.
http://www.ericchadwick.com/examples/images/Actions.gif
I have it set to Button mode so I can quickly click on them. I use colors for easier picking. Some I assign to hotkeys, but mostly I just leave the palette open all the time on my 2nd monitor.
If anyone wants any of these, I'm happy to share them. They're mostly very simple though.

Half Wrap, TB Wrap, and LR Wrap I use a lot for painting out seams in tilable textures. These Actions simply launch one of the freebie filters I found here.
http://www.btinternet.com/~cateran/simple/
I find them faster than typing values in the Offset filter, since they're relative not absolute... they always Offset in halves.

This one seems like the best auto-tiler out there.
http://www.seamlesstexturegenerator.com/
I'll buy this one if I end up having to do a load of tiled textures.

The Nvidia DDS and normal map plugins are great too, very helpful. Doug Rogers has been very responsive and helpful with my queries about these.

For painting on cubemaps, one of the best tools I've seen is an old one called SkyPaint. http://www.skypaint.com (http://www.skypaint.com/)
Not a freebie, but it does let you export any angle to PS for painting, then it swizzles the changes back into the 6 bitmaps again.

For extracting normal maps/height maps from real world sources, this tutorial and free toolset is really great.
http://www.zarria.net (http://www.zarria.net/)
Ryan whipped out a 1024^2 version for me by request. I think the one on the site is still limited to 512^2 max.

[EricChadwick]

Kevin, I finally had a chance to play with Mipster. Nicely written NVJavaScript.PDF, it's very helpful.

Can you elaborate a bit about sharpening between normal map MIPs? When you talk about fading you say "This disparity will be even stronger if you use sharpening between mip levels (often advisable for normal maps)." Do you mean just setting Mipster to use Sharp?

It seems that Mipster is disregarding my alpha channel. Would it be possible for it to MIP that also? I'd like to store height or glossiness or some other data there. I think it would help if the script placed the alpha-based MIPs into their own Layer Set (so they can be hidden en masse, and after editing they can be merged down into the Alpha channel).

Thanks again.

[KINGOMONKEY]

I was just wondering ( and i suppose im right?) can you have totally differnt images for the mip maps?
For a wild example if you were using alpha'd planes could you use dogs for the distant mips and cats for the close ups?

or alternatlively my idea was to use it to generate a type of fogging where in the distance all the mips are set to white but only the closer mips actually have any texture.

Hope you know what i mean

Thanks

bye the way, although a bit boggling for me, it was inertesting to read. Thanks

[EricChadwick]

could you use dogs for the distant mips and cats for the close ups?Yes you could. Although the transition between mips would be very odd, a half-blend between dogs and cats.

fogging where in the distance all the mips are set to white but only the closer mips actually have any texture?Yes, and the Nvidia DDS plugin has tools for this, so you can specify any color you like and which mip levels to add it to at whatever %, and/or you can fade the alpha, etc. Pretty cool. You can also hand-edit the mips yourself if you like.

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