Oblivion bubble ship

[Michael Lobko-Lobanovsky]

My Blender AO shadows seem sharper and cruder than yours and that's why I didn't present my own versions at once.

Here's a nice tutorial on AO baking in Blender.

The voice is irritating but the tips and tricks to make the shadows smooth and precise are cool. In the AO bake section of UV map editor, make sure to tick the Normalize checkbox; Blender will normalize the map shades against the white level, and the AO map background will also turn to pure white. Don't forget to adjust the margin width to some 5 pixels.

In a multi-mesh model, just select the desired mesh whose AO you're going to bake in the current iteration, in the mesh tree pane of the UV map editor.

[Patrice Terrier]

Here is my AO (PSD) reworked copy, is it any better 

[Michael Lobko-Lobanovsky]

Alas my friend,

Those maps seem to be a little better at some places but the others are still not good enough... 

And certainly the Photoshop tool chain is far more laborious. We are going to be much better off and safer with Blender and its AO margin/normalization/number-of-samples options if C4D doesn't have their direct equivalents. And we'll be more professional, so to speak. The safety margins make the AO map background color issue totally irrelevant to the final look of the model.

The tuto I pointed you to contains all the know-how to generate efficient high-quality AO maps in Blender real fast. It will also make our tool chains closer so that we'll get more competitive in case something in the model needs a quick fix or two.

[Patrice Terrier]

Thank you for the feedback.

Here is another copy with better antialias.

[Michael Lobko-Lobanovsky]

OK Patrice,

Here's a full set of Blender AO maps alongside your set of C4D AO maps.

The Blender maps have been generated fully automatically without my intervention with 20 ray tracing samples, 5 px margins and normalized to the white level. They look much much smoother and uniform throughout the entire model.

However they don't eliminate the jaggies completely. As it happens, the jaggies are due to how Blender/C4D ensure the transition from lit to hidden (fully occluded) areas, which appears too abrupt. (see the picture below)

Sadly the transition gradient cannot be controlled in Blender, and I suppose neither can it be adjusted in C4D. Of course, the UV's of respective offending border polies could be corrected manually after the AO maps have been baked but it would require much manual effort. Probably the transition borders could still be smoothed out to gradients by blurring the entire map in Photoshop?

On the brighter side of things, the C4D and Blender maps seem to be generally compatible.

[Michael Lobko-Lobanovsky]

More on AO Jaggies

It isn't Blender/C4D AO algo alone that's responsible for the jaggies. The current uber-shader is also taking its toll.

The shader original code used the AO map in its ambient channel only, which led to the shadows being almost never visible. Not only is ambient lighting rarely used in our models at all even at its weakest settings, but it also is generally the weakest, the least noticeable lighting component in the final color intensity of the screen pixel even at its maximum 1.0 setting. Thus roughly, the screen pixel final color used to be

Pix_final = (Col_amb * Map_AO) + (Col_diff * Map_diff)

In other words, the AO map did not affect the diffuse component (the strongest one) at all and we wouldn't see the AO map jaggies (nor the AO shadows, for that matter) when Col_diff happened to be bright, and Col_amb*Map_AO, pitch-dark for whatever reason.

I thought it wasn't correct either logically or visually. We do see object shadows in the real world when there is no ambient lighting around (no surrounding scenery for the light to scatter by and/or reflect from) and there is only the very distant sun shining down upon the object, which is what the directional diffuse lighting component is supposed to emulate.

So I changed the shader code roughly in the following way:

Pix_final = (Col_amb * Map_AO) + ((Col_diff * Map_diff) * Map_AO)

so now we're seeing beautiful shadows under any amount of the always-present diffuse lighting, and these shadows fade out smoothly and gently as we're dimming out the scene lighting with our "stray light" fader.

I think we should stick to this lighting scheme further on. Which also means we should find a technique practical enough to mask off, minimize or eliminate completely the jaggies we're seeing now in some extreme cases like this drone 166 model hull meshes.

What is your opinion about all this, Patrice?

[Patrice Terrier]

First let me say thank you for your efforts.

BTW it helped me to detect wrong meshes holes that i didn't see until now.
My eyes are not so much accurate that they used to be… 

I shall fix the gap hole first of all, then i will change the color shader to follow your suggestion, and once done i will give you my feedback.

[Michael Lobko-Lobanovsky]

My eyes are not so much accurate that they used to be… 

Your eyes are almost perfect, my friend. I think your eyesight is going to be your last sense to fail.

But no, you don't have to change anything in the shader proper. The one you have now in your sources has all my mods already implemented. I just described to you what I did in the past and why I did it. Regretfully my mods also (partially) caused those jaggies to be seen in the drone model, or at least promoted their visibility. But I still consider this as a very special case seldom observed in the majority of other models, and thus I vote for keeping the shader behavior as it currently is in our "reference" ObjReader code.

[Patrice Terrier]

Regretfully my mods also (partially) caused those jaggies to be seen in the drone model, or at least promoted their visibility.

I can live with it, as long as i am able to clear the most obvious jaggies with the help of PSD.

[Patrice Terrier]

That is my last and final attempt for that model.   

[Michael Lobko-Lobanovsky]

I've tried different modes to blend AO with the diffuse channel in the shader instead of our current multiply blending. All of them are either visually unfit for the purpose or make the jaggies visible at critical places. There's only one method I know of to suppress them reliably whenever necessary, which is to motion blur the offending regions selectively in Photoshop or alike.

I think we can't refuse to use the AO maps in our models or restrict their usage to the ambient channel only.

[Patrice Terrier]

There's only one method I know of to suppress them reliably whenever necessary, which is to motion blur the offending regions selectively in Photoshop or alike

Yes, this is what i did, and i can live with it, because the resulting quality is worth the extra work.

[Patrice Terrier]

And finally, here is the mixed version…

Bubble ship is flying under control of drone 166 until there is a pilot on board.

[Michael Lobko-Lobanovsky]

The picture looks very cool!

My comments will follow tomorrow night when I'm back home from Lithuania.

[Patrice Terrier]

I keep trying to put a pilot inside of the cockpit