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Volumetric Light controls

Posted: 14 Sep 2018, 04:43
by dgrantham
1) Can it only be controlled by the layer it's on? i.e, could it render on one layer while the voids determining its penetration areas are on another layer.

2) This is connected to #1,I suppose: Can the light beams it renders be assigned to their own layer?

3) Can a source be blocked from coming though one void but still come through another?

4) If the source is placed outside the page, it bleeds around the edges, so the foreshortening of the rays is restricted to the rather wide angle resulting from the source appearing to be quite near the 'viewer'. Can the user adjust this?

Re: Volumetric Light controls

Posted: 14 Sep 2018, 13:24
by melanie
Can you show us examples please?

Re: Volumetric Light controls

Posted: 16 Sep 2018, 10:02
by Peter Wassink
did you try the "Image Source" FX"?
it can be found in the FXpanel under "color" and it channels whatever you choose to be the source for the subsequent stacked fx's

Re: Volumetric Light controls

Posted: 17 Sep 2018, 22:58
by dgrantham
by melanie » Fri Sep 14, 2018 2:24 pm

Can you show us examples please?
I have adjusted the colour of the light and made an alpha hole for it to enter through; the light is coming through the hole into the image. The angle of the entire beam of light is too acute but how it naturally radiates can be adjusted by moving the light.
VolumetricLightAngleTooAcute2.JPG
VolumetricLightAngleTooAcute2.JPG (60.39 KiB) Viewed 1957 times

I can mask the overall beam into the shape I want, but now it can't easily be simply changed/animated by moving the light. The shimmer beams are narrow, as I'd like, but of course out of alignment.
VolumetricLightAngleTooAcute.JPG
VolumetricLightAngleTooAcute.JPG (95.28 KiB) Viewed 1957 times

Attempting to create something more controllable with the light source and more aligned shimmer beams, as soon as I take the light outside the project window to begin to make the angle of entry through the hole more realistic as a distant sun would be, the light now beams across the entire project. There is no point of entry within the project. If from outside the project it could be made to respect the hole in the image, much would be solved.
VolumetricLightAngleTooAcute3.JPG
VolumetricLightAngleTooAcute3.JPG (35.49 KiB) Viewed 1957 times

As I take it further away that issue remains and though the shimmer is now aligned, I can't get the beams narrower than this (I guess it can't be finer than one degree.) The light colour drastically shifts but I suppose that can be adjusted.
VolumetricLightAngleTooAcute4.JPG
VolumetricLightAngleTooAcute4.JPG (31.76 KiB) Viewed 1957 times

I can activate the mask again, but it's not the effect I'm going for, nor can it be simply changed/animated/controlled by just moving the light source.
VolumetricLightAngleTooAcute5.JPG
VolumetricLightAngleTooAcute5.JPG (70.82 KiB) Viewed 1957 times
I am guessing these are all the options possible, but I thought I'd post and enquire.

Re: Volumetric Light controls

Posted: 17 Sep 2018, 23:01
by dgrantham
by Peter Wassink » Sun Sep 16, 2018 11:02 am

did you try the "Image Source" FX"?
I tried that thanks to this suggestion, Peter, (to solve a lsightly different set of issues than the above) but I couldn't get a source within that operator to have any effect on the light.

Re: Volumetric Light controls

Posted: 18 Sep 2018, 12:53
by Peter Wassink
you could do this:
(see image)
Screenshot from 2018-09-18 14-14-45.png
Screenshot from 2018-09-18 14-14-45.png (45.28 KiB) Viewed 1940 times
its the vol.light FX applied on a layer with a blackshape.
if you animate that black shape than this will dictate the movement of your shimmer, and the beams will have the correct angle as determined by the distance source point.


#edit
effects like these are only doable with tvp up to a point.
You run into the limits of the the 8-bit architecture (banding!) pretty quickly if you are trying subtle light animations