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Sorry I posted this already in the modo forums, but it doesn't seem modo specific the more I am digging into it.

I read the docs and didn't see anything about it but shadow pass does not work with fast ML preview? It like deleted my shadow pass when I tried and switched back to diffuse and reflections. I noticed when you use that it turns your main render basically into a previewer, which kind of segways into this....

So then I tried to render out another one with fast ml preview off. (This is just with the shadow pass checked) and i adjust my ML sliders and in the preview window it adjusts the lights, but in the preview window it shows a render with the reflections and diffuse on it. Then it will update my shadow pass in the main render window properly.

My concern is though, is it taking the time to calculate diffuse and reflections even though it is unchecked? I have read that it does full global illumination for the shadow pass, which makes sense. But is it spending extra time on rendering relfections in glass and surfaces that are going to be alpha'd out?

I hope I explained this good enough. Just in my mind, even if it is doing full GI it should be faster than a normal render. Especially in my case where 95 percent of it is alpha'd out and I have the bottom 8th of the image as a shadow catcher that is actually visible.

I am sure in the future I will just render the diffuse and reflections and shadow pass at the same time. But I just learned about it and want to render them separate.

Thanks

Cody

More pictures, less words.

I dont know what to show, I will try and explain it better.

I just did it with a scene with just a shadow catcher floor and a red cube.

Try to just render out just the shadow pass for it, in the preview window it renders with the diffuse and reflections. Then you adjust your sliders for ML and hit refresh. After the next SL level it will refresh the shadow map in the main render. Makes sense. But does that mean it is rendering out reflections and diffuse for the preview window? Is that wasting render time is my question?

But.... try to render out just the shadow pass for something with ML andddd fast ML preview enabled. Everytime you move a slider it will change your main render back to a diffuse and reflection layer.

So basically when its either the previewer without fast ML enabled, or when the main render is fast ML enabled, it is rendering diffuse and reflections when you adjust ML. Is this wasting render time?

In my mind it should just be a shadow map, whether it is in the preview with fast ML preview disabled or the main render when fast ML is enabled.

Maybe I am wrong, but does the diffuse and reflections have anything to do with shadows?

Thanks

Cody

A shadow is the absence of light, so yes calculating where the light is, would be quite useful.... Back to school for Cody me thinks

May the grammar be with you

I think Cody is saying the cpu is wasting resources rendering the full image when he just wants a shadow pass only.

Bubbaloo wrote:I think Cody is saying the cpu is wasting resources rendering the full image when he just wants a shadow pass only.

Ding ding ding...

Gosh these forums are deadly I couldn't imagine someone with a low self esteem. Not trying to be rude but damn..

LOL These forums are not for people with heart problems or high blood pressure.

wasting resources rendering the full image

Erm , isnt that the same thing? .. as calculating the light? I dont see much waste.. so no mis-understanding really is there?

eric nixon wrote:

wasting resources rendering the full image

Erm , isnt that the same thing? .. as calculating the light? I dont see much waste.. so no mis-understanding really is there?

"How many images are being rendered concurrently?" is the question here.

I guess just render the diffuse + reflections and shadow pass at the same time for now on and just not worry about it.

I understand forums all to well. I shall earn my keep. And take in less sugar;)

To expand on what Eric was saying, since the shadowpass in Maxwell takes into account the full GI of the scene, including for example reflected caustics that might brighten up a part of a shadow, then the "full" render still needs to be done. So you still need to calculate the full light paths.

Got it. Thanks Mihai, like I said, I will just be sure to render them both at the same time. Post it note on the monitor.

You don't actually need to make sure both are checked, the Shadow pass will still internally render a full render. This is why it can be one of the slowest passes to render. But it's a very nice and accurate shadow pass Even, if you have ML on, and you change something, the shadow pass will update correctly.