How to exclude objects from the AO at A+Dmaterial level?

[nisus]

Hi All,

The problem of excluding objects from the AO on the A+Dmaterial level have been bothering me for a bit. how can I solve this?

To explain the situation. I have several objects that are wrapped up in a plastic wrap. The objects need AO (added as a special effect in the A+Dmaterial) because otherwise the rendersettings would be to high for the detail I'm after (and I need fast render times because I will need 4x +5000frames of animation...). the plastic wrap should be transparent, but underneath the wrap is an unwanted 'AO-shadow'. How can I get rid of this?

rgds,

nisus

[nisus]

Hi All,

On top of this, I got another issue with the AO at material level...

The visibility track does not work correctly with MR, so when fading objects can best be made by animating an output map in the cutout slot. This works fine, BUT the object will still be 'visible' to the AO of the surrounding objects, thus leaving an AO-shadow on the object, even when the first object is 'invisible'. Hiding this object helps, but how can I make a SMOOTH transition?


rgds,

nisus

[hot chip]

hi,

most i am use the AO as a mix_map, and then i can animate the color-slots for example: from black (shadow) to white.

[MasterZap]

Hi All,

The problem of excluding objects from the AO on the A+Dmaterial level have been bothering me for a bit. how can I solve this?


Don't use the built in AO, but then apply the normal AO shader to the "fg_weight" input, which will end up being the same thing, but you have all the bells&wistles (exclude etc.) of the standalone AO shader.

/Z

[nisus]

Hi Zap,

Tnx. Unfortunately, I have no idea where to find the "FG_weight" to apply that AO shader (I use the max interface only). How can I reach this fg_weight from within the A+D or a mental ray material?

rgds,

nisus

[nisus]

Hi all,

I tried to find a workaround for my problems by animating the AO Max Distance - 0 for invisible and whatever value for visible - BUT when I try to animate this value, it automatically switches to "1" and kind of hangs, because I cannot set the initial value anymore.
Is this an known issue or is it just me?

rgds,

nisus

[nisus]

ok... it's just me... I had my default controller type set on ON/OFF (because I'm animation visibility tracks)... OMG!

rgds,

nisus

[nisus]

... the workaround doesn't work either, because it is NOT the fading object that needs the animated AO, it is the surrounding objects that would need this... and as there are several objects around, there is no way to seperate ONE object from another...


Ok, maybe Zaps trick with all kind of ID's for exclusion would work. But how do I do this SIMPLE? (I'm making a tutorial for the assembly of a door (with all screws, nuts and bolts) and it feels rather insane to start doing this

One solution might be NOT to use AO (and boost the FG settings), but I won't be able to render 4x +5000frames in less than 2 minutes a frame... Also... saving FGmaps is not an option because every single frame objects move...

Any thoughts on a simple solution?

rgds,

Nisus

[MasterZap]

Hi Zap,

Tnx. Unfortunately, I have no idea where to find the "FG_weight" to apply that AO shader (I use the max interface only). How can I reach this fg_weight from within the A+D or a mental ray material?

rgds,

nisus

Pardon, in the Max language, it's the "FG/GI Multiplier" over in the "Advanced rendering options" rollout.

/Z

[MasterZap]

- Using FG with short falloffs?
That might work, gonna try that in the morning ,-)


- Simply excluding your "fading" objects from AO, calling that "artistic licence".
Nàààh. Won't work... I would have to exclude almost ALL objects...


- Render the "fading" bit in post, so the frames for which some object fades in, render that section overlapped, then do a post fade.
Ok for a few objects, but not for +1200 with overlap...


- Let objects magically "pop" in with a nice sound effect and a flash of light ;) (Fading is soo 1980 ;) )
True. MR even has a special feature for it: a non-working visibility track ,-) Well, I've been animating a lot without the fades now... It really doesn't matter so much... and saves tons of time...


- Don't use AO, but a large area light
I should perhaps try this, although I'm afraid I would need LOTs of samples to get the same smooth result... Anyway, worth a try... Can't win if one doesn't get in the ring ,-)


/Z
/N


tnx! & rgds,

nisus