Multi Chan Hax

Looks like I got it and I'm so happy. I can now switch between a bunch of mapping channels in the same file. And I actually managed to change the data to an indexed structure withough confusing myself to no end.

~does a happy dance~

The data files are *so* much smaller and contain more than two channels. I be all like, I wonder what this looks like when I use this mapping channel? Then I be all like, gonna switch to that mapping channel to see what's up. And then I be all like, it's all good!

Not only do I already have a bunch of general mapping channels ready to go, but I can quickly churn out specific purpose data sets. Oh, here's a data set with five different head angles in it for quick-n-sleazy photo-sourcing of faces. Now I'm in the mood for making some jeans, so here are some leg seam-blasting channels. How many shoulder and neck channels do you want? Gimme four of them.

Okay, so I don't have it ready to go out just yet - but I do have it working. A few more little things and a few MCH files to get you started in a day or two.

I'm so happy.

wow sounds great!
post some pics?

What is a mapping channel?

The only meaning I can attach to "mapping channel" is too trivial to bother making a post about, so most likely I just don't know what it means at all.

LoL Abu, I was folowing your earlier post on it and went through your material on your site and I was like...daaaaaaaaaaamn...I need to get into Max more often and outta C4D. I think what's really cool is you just outlined some of the uses that are possible with it that some of us wouldn't think of.

Just wanted to say thanks for sharing it

Sue, a mapping channel is UV coords. For example you can have any number of alpha channels in the Channels palette in Photoshop. Kind of the same idea, you just have to tell your software which one to use.

One of the easier example of mapping channels is the head. Let's say that you have a master mapping channel that your final texture goes into. This would be the head template for the SL avatar mesh that lots of folks around here are familiar with. Now let's say that you find two really good reference head shots that are front and side. While it is possible to blend them to the master template, mapping channels make it a bit easier. So you add two more mapping channels: one is the front shot and the other is the side shot. You can then take those and let the software mangle the pixels to the master template. Once you have that, blending because much easier - and the added bonus of making seams so much easier to deal with.

I'll be working on some examples and what-not this week.

Right now things are a bit haphazzard. I want to get the bare-bones up for those that are 'in the know' started. And then start to bring the rest of y'all up to speed as I work on tuts and stuff.

http://tech-slop.serveit.org/wiki/index.php?title=Multi_Chan_Hax

That is the version and file format that I will be running with. The extension is the same, but not compatible with Map Chan Hax. That is, I highy recommend getting rid of Map Chan Hax and the other related files that I tossed up for it.

Multi Chan Hax looks pretty much the same and shouldn't be too hard to figure out.

There are also two different data sets for the SL mesh in a single zip.

SLF_maintorso_3chans.mch: this one is the bulk of the torso and has some leg action.
Chan 1 is the Trip channel that I used in the earlier thread.
Chan 2 is unwrapped from the front with the main seam down the middle of the back.
Chan 3 is unwrapped from the back with the main seam down the middle of the front.

SLF_legsonly_3chans.mch: the legs, or lower template only.
Chan 1 is the default lower template provided by Linden Lab.
Chan 2 is the front of the legs with the main seam down the back of the legs.
Chan 3 is the back of the legs with the main seam down the front.


I'm WinXP SP2 with PS CS2 and it functions just fine for me. This should work with other plug-in filter hosts, but I don't have a way to verify exactly which ones.

I'll get started on the To Do List this coming week or so to fix up some of the little things. Give it a memory so it dumps you in the last used directory, fix the slider values for when you load an MCH file, and finish the wrap-around. Things like that.

And I have to give the MaxScript another quick romp just for Pygora.

Hopefully that will be enough to keep y'all busy for a bit while I hack things out.

Haha! Thanks Abu.

I have to say that your script gave me an idea that made me start digging around in the Maxscript help files to figure out. I was going to rip off your UV reading code then get into figuring out the meshop functions to make a script that would output a polygon model based on the UV layout.

However, someone beat me to it with a script called SlideKnit http://slidelondon.com/iv They added a cool bit I hadn't thought of where the mesh based on the UV coords can morph into the 3d model. Perfect for adding geometry details to the flat model then attaching them to the model with a Skin Wrap mod and then baking and/or projecting them out.

Coupled with your wizardry this opens up a lot of texture tricks for artists that use 3ds Max.

"...to make a script that would output a polygon model based on the UV layout."

You can do that rather easily with Channel Info. Just copy the UVW channel and paste it into the geometry channel. Morpher and all that jazz. But I doubt I ever would have thought about dragging other geometry with it. Now that is a cheeky trick that might come in handy.

As a matter of fact, I used to make tangent normal maps using the UV <> geometry trick.

Careful, Pygora - you might start to enjoy lateral thinking a little too much. I know I revel in it way more than your average neurotic.

Hopefully later tonight I'll have a head tutorial up as an example. Earlier I spent a few minutes in Max setting up the channels, exported them, and got a damn good running start on a quick-n-sleazy photo-sourced head.

I still can't believe how much faster I can work with this new toy. No more baking a bunches of textures to different channels, constantly changing the materials to reflect different channel bakings, no more tons of files in a directory, and on and on. Close Max, move to Photoshop, and keep damn near everything nice and tidy with all of the 2d goodness that PS excels at.

Soon after I get some sleep.

Abu, I owe you my first born son... or a case of beer... or a damn good bottle of red!

Your contributions to this forum have been some of the coolest things I have ever seen. The plugins you've created for Photoshop make it possible for 2D artists to stay in the 2D realm, but enjoy all the super-nifty-fabulous 3D tweaks you've come up with. You've certainly made me appreciate the power of the plugin .

You blow my mind! I wish I knew how you keep coming up with these things, you amaze me! And THEN you share them freely with everyone!!!! YOU ROCK!!!!
Thank you, thank you, THANK YOU!!!

Thanks, Claire. I must admit that it is kind of weird for me to see that level of enthusiasm. Most either have a passing interest or think that I'm a total nutter. Again, thanks.

Some of my stuff is born of desire. I want to something so I make it. I don't always nail it right away, but I usually do get there.

A lot of other things that I play with are just plain curiosity. What if I do this? Do I have to use that? For example, yesterday I was thinking about mapping channels and goofing around. Usually a mapping channel is created and designed for various texturing reasons. Do you have to design a mapping channel with texture things in mind? What if you base a mapping channel on ambient occlusion? About 20 minutes later I was coming up with faux lighting solutions and applying them in Photoshop using MCH.

When you use Channel Mixer in Photoshop, do you have use RGB as colour channels? Certaintly not. You can toss whatever you want into the seperate RGB channels and then fire up Channel Mixer.

Filter > Distort > Displace moves pixels around using XY position. What if you toss actual pixel colour values around using the same method?

What if you load the AV mesh into Max, make it Cloth, and run the simulation? What will happen if I apply a force to splat it against a wall? Or pin the wrists down? OMG I just about died laughing when I did this. I even considered exporting these experiments as sculpties, but never got around to it.

Seriously, I could go on forever about silly ideas. I don't know. I just love asking questions and goofing around.

Anways, here is what I did this morning for the Max users:

http://tech-slop.serveit.org/wiki/index.php?title=Multi_Chan_Hax_MaxScript

In the next few days I think I will work on the file format stuff. If you are clever enough, you should be able to cull the format from the script. But I should talk explicitly about the simple file format that I used, which I'll get to next.

This rocks, Abu. I don't think it'll replace my existing workflow (which is very similar to this but not locked to specific angles) but for people without a 3d app this will be VERY useful.

Hmm... confused for a minute there.

Re-did the shoulders and down the sides of the torso for MultiCH.

The attached zip contains the MultiCH file for the newer remap on said areas and the vector template for the additional channel.

I did mirror it, but it's off by about 1/2 of a pixel or so (that's what happens when I try to eyeball it using 256x256).

When you go back to the default UV, the left side will be mirrored. Not the entire left side, but the mirrored part of the shoulder that is mirrored in the default.

I did try to find a decent compromise between having enough room to move and not doing everything. For the most part I am happy, but it does get kind of tight in a few spots. Not really sure how well it will work for the kinds of lines required for clothes work, but should be okay for skin work.

To see the correlation, I highly recommend running Chip's or Robin's upper template through it. If I get the gumption, I might put something together to make the correlation easier to see.

edit:

Something went wrong with the default UVs in the attached zip. Some tweaking needs to be done because some of the chunks are off by a few pixels. No idea how this happened, but I'll fix it.

Since Abu released his MaxScript code for his UV to MCH converter I've played around a bit with setting up UVs and moving pixels around. I thought I would share a couple of the more useful UV layouts.

The uploaded templates and MCH files (with vector paths for the UVs as well) are for the immediate areas around the seams between the head and torso, and the torso and legs.

Obviously you can use this to paint lines across these seams that will line up without guess work. You wont be able to paint the whole body willy nilly, but it can be used as a starting point and then split out to the proper UV space for the rest of the texturing. With Abu's channel switching you can also grab the areas from two maps and combine them into one for touch-ups or aligning and then split them back apart when you are done.

Thanks again Abu!

Here's a MCH/PSD set for the avatar head. It is a spherical UV projection that has most of the distortion on the top of the scalp.

For best results set the template to 2048 x 1024 and then square it back up after you transfer to the SL UV coordinates.

Another trick: If you have access to 3dsk type references, you can use Photoshop's Photomerge to stitch together the starting basis of a texture using this map.

You go, Pygora.

I can't wait to take your head one for a spin this coming weekend. Doing the more common spherical head is one that I've been delaying. I've done a few, but they weren't exactly proper or the greatest. For some reason the area around the eyes always gives me major problems.

Let me know how it works for you. I'm always up for making improvements. From what I can tell I'm weird in that I don't mind the black art of UV unwrapping. I used to do the seam spanning UV trick with Render to Texture every time I did a texture set instead of just making a general purpose UV set like a sensible person.

I just took your head unwrap for a spin and am mightily amazed. Two things that I noticed immediately. No inside of the mouth and you did the ears right on the head. The ears?! OMG the ears rock. Just when I was thinking that I was the psychotic one, you go and do the ears like that. Heh.

And the eyes and nose areas look good (problem areas for me).

You have managed to put a smile on my face. Kudos.

Good deal! The trick is to use UV relax tool with low iterations on the problem areas before getting in there by hand.

I can throw the inner mouth UV's in if you want. I think there's enough space there. I didn't include them because I just don't think about them personally when texturing until after the outer skin is done. This layout was for using the photoshop photomerge tool and stitching together front, 3/4, sides, and back views and tweaking stuff into place with liquefy and warp for a nice texture start. I would do it different if I was going for a hand paint texture layout for example.

The avatar ears are a source of amazement to me. There are over 175 faces in each ear! And yet they are so under-detailed given that face count. On top of that the amount of UV space given to them is huge. You can cover half the frontal face plain with one of those suckers.