Some Text on Textures

I decided to write a post about the current state of texturing the rocks and cliffs for scene 1.

Although far from finished it is a first approximation of what I am aiming for.

After the various expeditions into cloth and hair land I thought that texturing was a voyage into known territory. As like so many preconceptions during the development of this project, this turned out to be some wishful thinking again.

The topics I encountered so far a many and quite diverse. Currently I am at iteration level 4, with twice a complete modeling restart and 3 scultping reworks.

Its a delicate balance you have to do between the amount of modeling, scultping and texturing. Doing it wrong just gives a fake feeling for the cliffs when viewed from different distances. And due to rendering time limitations I refrain from using extremely detailed displacement maps ( with accordingly high poly count cliffs) and try to cover this with bump/normal maps.

I also do not longer sculpt the high details for normal map baking. This could work out if the texturing were painted exactly to the fine details, which turned out to be to much work compared to what is actually gained.

For the scultping I use the GSOC branch from J. Wilkins available from graphicall.org.

The texturing is done with the current blender 2.5 svn trunk. It took several attempts to arrive at a suitable workflow. With my previous projects, I never seriously used the projection painting system from blender. For Ara’s Tale though I wanted to use this feature.

I ended up with a mixture of projection painting and working in gimp, which unfortunately is far from efficient and even leads to compromises I didn’t intend to make.

When working with graphics I massively make use of layers and masks and try to implement a non destructive editing workflow. A typical use of layers is to test things, play around with blending modes and keep different versions in one file, being able to go back and switch between texture approaches.

Alas this is a non-option with the current implementation in blender. Whats even worse are the limited painting modes, with the missing overlay mode the most prominent. The brushes are also a bit limited.

A way out of this would be the ‘Quick Edit’ feature but I had no luck to get it working in a consistent manner. Reapplying the external edited projected image always resulted in either a tinted texture (which I was able to trace back to hemi lights active ?!?) or just a darkened image. So multiple uses of this feature leaves you with stripes and too dark an image.

What I do now is to use the projection painting to layout the basic texture and work on the seams. It works quite well to almost erase the border seams between different objects. The resulting texture is loaded into gimp and here he high frequency details are added. Back in blender the seams get cleaned up again and some stretching from the gimp editing is corrected.

For the cliffs I decided to use grey scale photo patches. With this I am able to design the basic structure. based on the greyscale texture I start coloring and have a base for the bump maps.

I am using photo textures all taken by me during my last visit to arco/italy.

See here for some photos to get an idea of the environment there. ( lighting quality is bad from a photographic point of view, as I intentionally went to places which were in shadow to get only diffuse lighting, which is best to take textures )

I took some 150 high res RAW images which now is my base for all the various rocks in Ara’s Tale. All were converted to greyscale, a bit sharpened and lightness corrected to have a consistent texture base.

An important issue was to keep the same scale across all the different cliffs. I used a reference object as starting point for the zoom factor and subsequent project painting. It also helped to have a model of Ara there during painting to fit the rock texture the scale of a human being.

All this said I am still not 100% satisfied but anyway here are some samples of various cliffs of scene 1. The lighting varies over a wide range and hints at the next major headache. Right now its a bit on the dark side and you may have to have a properly calibrated monitor to see it correctly.

And finally here is a shot with some textured cliffs to show how this all works when animating.

Oh, and I almost forgot, I also did some work on the texturing of the cage.