Ptex could be even better..

[splodge]

Ptex support is nice but I think it could be even better. At the moment it's a little technical and quite wasteful, yet it doesn't really need to be.

So my suggestion is that when starting up ptex mode it could be possible to have 3D Coat set each polygon's UV space to the maximum amount and then let the user paint with maximum detail without having to worry about the technicalities of resolution etc. Then when the user finally exports their model 3D Coat could optimize the UV space and compress the texture data so that each polygon only takes up as much texture space as necessary. So in theory a polygon that has blank texture data should only need a single pixel of texture space, yet a polygon with lots of detail (detail=sharpness) would be given minimum compression. While a polygon with medium detail (blurred pixels) would be given a medium compression. Note that compression in this scenario really means texture space size reduction.

ZBrush has something similar to PTex called 'UV Tiles'. In ZBrush the user just specifies their target texture size and then ZBrush automatically generates the tiles and uses up the entire texture space. But at the moment ZBrush doesn't do any form of compression. Instead large polygons are assigned a larger texture space than the smaller polygons regardless of whather there's any texture details present within any given polygon.

So adding compression would mean that in theory the entire texture could be as small as 32x32. Whereas at the moment with the current ptex implementation a texture is always going to be a minimum of 2048x2048 regardless of how much detail is present!.

By the way:

I once programmed my own texture compression routine that would reduce a textures size depending on the contrast of neighboring pixels and so I'd be happy to offer some tips. It's really simple, it just means scanning through all the pixels and comparing neighboring pixel pairs and measuring the color difference between them. The greatest difference is what ultimately determines the sharpness rating of the overall texture/image and the texture's size is then reduced accordingly. So a large gradient filled texture could be reduced to just 64x64 pixels. While a texture with just a couple of contrasting neighboring pixels wouldn't be reduced at all. This type of compression would be ideal for Ptex.

[ldzywsj]

Hope Andrew can understand you!

[splodge]

Hope Andrew can understand you!

haha even I struggled to understand it when I read it back to myself!. It's a rather difficult suggestion to describe.

[pbowmar]

FYI, Andrew followed the Ptex spec from Disney, so it's unlikely any changes he made would be useful. The whole point of Ptex is for the .ptx files to be loaded into a PTex compatible renderer, like Renderman and (soon) others.

Not that these are bad ideas! Just that Ptex is a specification, not something Andrew made up and controls

Cheers,

Peter B

[splodge]

FYI, Andrew followed the Ptex spec from Disney, so it's unlikely any changes he made would be useful. The whole point of Ptex is for the .ptx files to be loaded into a PTex compatible renderer, like Renderman and (soon) others.

Not that these are bad ideas! Just that Ptex is a specification, not something Andrew made up and controls

Cheers,

Peter B

Hi, Phowmar.

The great thing about my suggestion is that it doesn't really change anything about the ptex file format. The only difference is polygons with blank or blurry texture data are optimized/compressed to use minimum texture space.

And I suppose if somebody wanted to get involved with specifying the texture resolution for every single polygon then they could still use the ptex tools present in 3D Coat.

[Roger_K]

PTEX is about escaping UV Tiles and only storing what data you need on a per face basis. Starting with each faces at some arbitary max resolution just wastes RAM and removes all the workflow benifits of PTEX, the idea of PTEX is that if you need more detail then you add it to a focused area and spend your system recources on the important stuff.

Id personally just do a good uvlayout and paint it in per pixel, as it stands auto unwraps from PTEX are useless for anything that needs to be edited in another application.

[philnolan3d]

The main improvement I'd like to see for Ptex is that in the Disney videos they show a group of selected polys being laid out flat so that thy could be painted in 2D. If 3DC had this you could still use Photoshop with 3DC's projection tool and Ptex at the same time.

[michalis]

ZBrush has something similar to PTex called 'UV Tiles'.

Seamless? Try some displacement maps like this... Packed UV tiles is a better option, still I don't trust it. UV master is great but classic.