MEL message attributes

Listening To : Bill Bailey , Jimmy Cliff

MEL today.
Just found out about message attributes and connecting things together.
connectAttr and listConnections. Neato.

Also, thought for today is that in Games, the artists always seem obsessed with the characters animation, run cycles etc. and don't really care about lights or cameras too much. In post, lights and cameras are so much more important (duh). Yeah, well, not a fabulous insight - but was just thinking about the differences earlier today.

DNeg Free beer and pizza tonight, and my contracts just been renewed. Yippee!

the grids

Listening to: Nothing, i've lost my iPod charger cable

So to wrap up my previous post about the mysterious grid lines..

It turns out that in multiplying my derivatives used in the texture map lookup in order to blur the map, the usually unnoticeable discontinuities in derivatives around the shading grid boundaries had been magnified (by the multiplication).

I was doing this:-

duds * 25 = ...
dvds * 25 = 0.03 // for arguments sake, it's there or thereabouts
dudt * 25 = ... // similar order of result for the others
dvdt * 25 = ...

but sometimes the derivatives were very different around shading grid boundaries, so the tiny aliasing that is normally unnoticed, was being amplified and appeared as a grid.

The solution was to add a number to the derivatives to get roughly the 0.03 I wanted (so not 25, something much smaller instead). That way the aliasing would stay small, but I would still get the blurring I wanted.

So that's that.
Hurray!

brickmaps, pointclouds.

Listening to : Fiery Furnaces 'EP' and The Crimea's new CD 'Tragedy Rocks'

So it looks like the best thing to do for my st bake is to have "interpolate" set to 1 in bake3d to get micropolygon midpoints (from four sample points) instead of absolute points and also to avoid duplicate points being written out at the boundaries. Then, in texture3d, use "lerp" set to 1 so that it looks up from the two nearest mip levels and interpolates between them.

Curiously, I found that baking at 1200x1200 shading rate 1 gave one quarter of the points (2million instead of 8million) and was 80Mb instead of 345Mb, but had much much better results and a more consistent point cloud compared with previously at PAL res, same shading rate, when it had been patchy..
Maybe this was due to adding interpolate==1 as mentioned above ?? If so; way-hey! Interpolate is cooool!

(Note to the newbies - generally to increase point cloud density you lower the shading rate and/or increase the render res, which is what made this result so odd).

In the beauty render, I was seeing dark grid lines aligned with what looked like the shading grid. At first I guessed somewhere I made the classic misktake of doing texture lookups or area functions inside a branch instruction that uses a varying variable instead of a uniform one. This is such a common mistake when you're used to writing real-time code with efficiency in mind. However, after fixing these in the shader, it's still there, so it is probably something else..

Other problems I have at the moment are;
- the baked average ray direction looks grossly incorrect. Not really a problem but would be nice to get to the bottom of the cause.
- i'm getting some squares flickering.
- I still don't know why my brickmap is okay down to level 7, but has mostly black beyond that. It means I have to set maxdepth to 7 before I render the beauty pass... kind of a pain.