3D painting in Blender an alternative to Alpha Mod?

[obsidian]

I'd start to paint in the grass using a tiling texture, then the dirt with a tiling texture again, and so on. The brushes I choose act like brushes in photoshop. They automatically blend the edges and on top of that I can control the opacity of the paint/texture as well as brush size and so on. In my understanding I don't have to write a blend shader because the model would be exported with this one texture I already painted onto it; that already contains the blends I need.

Not quite. The method you are roughly describing requires the use of "sub-materials" which is not supported by Quake 3, though it might work for other games. If you are building terrain blending for Quake 3, you have to split the model into separate meshes, each mesh can only have one material assigned to it. The seams where two materials meet will require a blend shader. You control the opacity of blending by using either vertex alpha painting or alphaMod volume brushes.

I suggest you try some of the tutorials, starting with sock's terrain and then trying some of Kat's modelling stuff. I think you're still much too confused to make any sense of the entire process, particularly when it involves modelling and some of the limitations involved with Q3. You don't have to do an entire map, just a few small test maps to learn the basic concepts, then move on to bigger stuff in steps.

Would I run into seems between the individual md3 chunks because of the export-import?

You might run into lightmap seams if your surfaces are lightmapped. Kat tried to hide a lot of these seams in his geometry, tucking the seams to look like bumps and cracks.

[Ferrao10]

Ah OK, guess we're slowly coming down to it, to the misunderstanding.
I thought, painting on a model would mean (in photoshop terms) to paint on one layer. Or canvas. And with the export, it would all be baked down into one texture that would cover the final model as just one simple texture.

[Kat]

Re the forum issue: I've activated the account manually so you should be able to log in using the details you used. And no worries about not posting this, there's often valid cross-over.

If you're painting your mesh you don't need to worry about tiling too much because your end result is going to be a unique image asset that's specific to the object it belongs to (and yes, depending on what you did to 'paint' the mesh you may need to either 'bake' or 'save' the results). The downside to this approach is you'll potentially use/generate a lot of textures and/or they will likely be of relatively low resolution so you'll probably want to use a 'detail' stage in the models shader to hide that problem.

[Ferrao10]

OK. well now I am confused.
I'm at the end of my foolishness instead of wisdom, really.
Come time, I'll try to understand this material.
Baked textures still require several layers? Sorry, beyond my understanding and I don't have time for it . I'm out. But it was interesting .
I hope it will help some other people to learn and get into "modern" mapping.

Going back to carve the dinner table for our house. It's what I learned and do; working with wood. It teaches you how to handle it at a touch.
Much more intuitive than anything digital .

[sock]

Yarrr it was. And double yarrrr to generally encouraging public discussion about Blender and terrain generally.. yarrr!

My mistake, sorry. I thought the modelling conversation had gone to a PM.

I thought, painting on a model would mean (in photoshop terms) to paint on one layer. Or canvas. And with the export, it would all be baked down into one texture that would cover the final model as just one simple texture.

The process you are describing is painting the landscape as unique chunks or models. This is possible for sure, but you will end up with texture resolution problems (every model piece of the landscape will need a unique texture and models have limitations on their texture size), light seams along edges of where the models are joined (this is always difficult to hide) and a map that will require a lot of memory to load / run.

What you are describing is also what most modern day game editors do. A classic example of this the cryengine (http://en.wikipedia.org/wiki/CryEngine_3) toolset where you sculpt (push/pull tools) the landscape to the shape you want, paint the textures on, add models for details (rocks, trees, plants etc), add decals (roads, paths, extra grunge) and then fine tune the blends with additional textures. All this from the editor and it even works like a 3D package using 3DMax control handles on all objects! Really fun visual process, but that is because the toolset was designed that way.

I don't have time for it . I'm out. But it was interesting

Before you give up I think you should consider what exactly do you want to achieve with a landscape? Maybe you can create something that gives the right impression but is not overly complex. Creating Q3 terrain is very much like painting, but you are only really interested in the broad strokes, there is no need to paint every blade of grass in a meadow! The use of misc models (rocks, trees, plants etc) and decals (grunge) will over come the limitations of detail painting.

* Start with the broad strokes of where you want the single materials? rock walls, grass floors, dirt paths etc I always find that if you imagine the landscape as contours it will look much better when you come to blending later. (Contour example - http://www.compassdude.com/i/topographic-map.jpg)
* Define your landscape in single materials first and then export those sections as ASE files
* Setup up basic single terrain Q3 shaders, they are different to normal shaders because they use world co-ordinates.
* Layout the ASE files in a box map in the editor, compile, light and see what it is like?
* Tweak the landscape for scale and player movement, test again

Then comes the fun part, the blends.
* Take the section where two materials meet and create two stripes of triangles (got to allow the blend time to work).
* Export the blend areas as separate meshes just like the previous terrain sections.
* Setup blended terrain Q3 shaders, plenty of examples exist.
* Layout the new ASE files in the box map.
* Add alpha brushes to work on all the model edges that need to change, single material blend single material
* Compile, light and see what it looks like?
* If you are clever with your planning of the textures and alpha fade brushes, you can even achieve 3 way blending

Finally add all the detail you require as additional models, rocks, plants, tree's etc and remember to manually clip all the terrain sections. I would not recommend using the model autoclip function unless the terrain sections are not complex. You can even project decals on to the landscape for extra detail (paths, grunge etc) with the right textures.

As you can see, the bottom line is you are wanting to use a 10+ year old engine to do something that a modern engine does without much effort. Sure the Q3 process is long and complicated but usually the results are impressive, especially if you have got some good textures and additional assets (rocks, plants etc)

Here is some good examples of Q3 maps that are using terrain blending and/or blender models
Marilyn by Rota - http://www.lvlworld.com/review.php?id=2010
Angkor the flag by dONKEY - http://www.lvlworld.com/review.php?id=2171
Overgrowth by Despair - http://www.lvlworld.com/review.php?id=2154
little rock by kat - http://www.lvlworld.com/review.php?id=1854

[Ferrao10]

Thanks to everyone involved; for your patience mostly .
So, like my initial feelings, I had hoped for too much. It couldn't be that easy with the id tech3.
Thanks a bunch Sock, for that lengthy and understanding post. It did open my eyes.

I for myself would need too much time though to get through all that process, as I only have a limited amount of it for this hobby. It's back to rectangular shapes for me. And the occasional mesh, off course.
But maybe some of the younger mappers on here will find it interesting and build upon.