topic Re: Visible lights - Caustics in Visualization

Visible lights - Caustics

Anonymous — Thu, 11 May 2023 11:39:21 GMT

I can't get the visible light with a spotlight shining through the portal windows in this sanctuary to show. I think I have all the settings right but can't get it to change the rendering at all. I want to put in stained glass in the windows and show the visible light coming through. Any ideas?

Re: Visible lights - Caustics

Barry Kelly — Fri, 15 Aug 2014 02:08:09 GMT

Is this the effect you are after?
In the spotlight I turned on the visible light and set it to volumetric.
Other than that I am still trying to learn myself.

Barry.

Re: Visible lights - Caustics

Anonymous — Mon, 18 Aug 2014 15:59:27 GMT

Thanks that worked except the colored glass that I put in for the window glass doesn't show up in the rendering.

Re: Visible lights - Caustics

Karl Ottenstein — Tue, 19 Aug 2014 16:05:15 GMT

Did you perhaps only change the color of the material in the OpenGL tab of the surface settings, and not in the CineRender surface settings?

Re: Visible lights - Caustics

Anonymous — Tue, 19 Aug 2014 16:56:49 GMT

Karl wrote:
Did you perhaps only change the color of the material in the OpenGL tab of the surface settings, and not in the CineRender surface settings?

I applied a jpeg of stained glass to the glass part of the window and then attempted to have the beams of light shine through. I can set a color for the transparency but that doesn't show the jpeg.

Thanks for the ideas. I'll keep fiddling.

Re: Visible lights - Caustics

Karl Ottenstein — Tue, 19 Aug 2014 19:12:56 GMT

outpostarc wrote:
I applied a jpeg of stained glass to the glass part of the window and then attempted to have the beams of light shine through.

This is a great learning exercise. Glad you brought it up here. Setting the image of the stained glass to be in the transparency channel works for me in preview. I'm still waiting for the final render to generate though...

...and, I have no idea how to align the image to the desired position within the glass...

Re: Visible lights - Caustics

Karl Ottenstein — Tue, 19 Aug 2014 23:36:35 GMT

Took forever for the sample example attached to render. But, the result is kind of cool with the visible light picking up the colors of the jpeg image of a stained glass window.

I'm disappointed that I cannot figure out how to align the transparency channel image (jpeg) with the glass. I had sized the image as 6' x 10' and made the window that size. (Should have made the glazing that size of course... but still, would have expected alignment to be one of the lower corners of the glass - e.g., local surface origin.)

Re: Visible lights - Caustics

Anonymous — Tue, 19 Aug 2014 23:42:05 GMT

That's cool. What light source did you use and did you apply the image only on the transparency channel?

Re: Visible lights - Caustics

Karl Ottenstein — Wed, 20 Aug 2014 00:05:38 GMT

outpostarc wrote:
That's cool. What light source did you use and did you apply the image only on the transparency channel?

Yeah, I thought so too! BTW - I just tried this with Artlantis 5 which has so-called "god beams" for the sun/heliodon ... but while they project the stained glass image onto the floor, the visible light is just white - does not pick up the colors like here with CineRender. And has other issues (although it was fast). So, yeah: cool!

I used the Spot Light 18. It and just a few others allow for visible light.

Yeah, only used the image for transparency as in prior screenshot of surface settings.

Re: Visible lights - Caustics

Karl Ottenstein — Wed, 20 Aug 2014 00:18:23 GMT

Here's an Artlantis 5 render with the 'god beams'. Vastly inferior to the CineRender sample.. but I was wrong about the visible light color ... the beams do pick up a little of the color from the jpeg. But, this generated in a few seconds vs the couple of hours for the CineRender image...

Re: Visible lights - Caustics

Anonymous — Wed, 20 Aug 2014 12:14:06 GMT

Was your jpeg anything special? I just clipped one off of the web and I can't get the light to shine through like yours. Also do you need to use final for rendering quality to get this to work or can you do a quicker preview?

Re: Visible lights - Caustics

Anonymous — Wed, 20 Aug 2014 13:35:23 GMT

I'm still struggling to get this to work. My sample file looks like this.

Re: Visible lights - Caustics

Karl Ottenstein — Wed, 20 Aug 2014 16:02:29 GMT

Interesting. Darker/underexposed... but the quality of the visible light that there is is pretty cool.

Looks like you have both the sun and a spotlight maybe - otherwise I can't explain the projected glass color on the floor near the wall vs the shape of the visible light... and the visible light setting for the spotlight does not have a long enough distance... and so terminates where seen in the image?

To get my exposure (which is way overexposed compared to yours), I slid the blending slider for the normal-blended translucency jpeg to about the middle of the range to allow more light through for global illumination to illuminate the 'room'. Also used physical camera and unchecked the render setting box to use the sun. Only the spotlight was generating light in my test.

Will be away from my computer for a day or two...

Re: Visible lights - Caustics

Anonymous — Wed, 20 Aug 2014 18:23:36 GMT

Thanks for the help Carl. Still working on things but will try to get ready for a preliminary meeting tomorrow. I'm used to working in Artlantis but I'm hoping to get good enough to get some good images from C4D.

Re: Visible lights - Caustics

Karl Ottenstein — Fri, 22 Aug 2014 16:31:47 GMT

That's getting there, Mark. Nice.

For Artlantis, a correction to what I said earlier - about there only being visible light for the sun via "god beams". I hadn't used the feature in Artlantis 5 since beta and had forgotten... certain light sources in 5 have a check mark and slider for "light cone" which does indeed generate visible light beams that pick up the jpeg color - and super quickly compared to CineRender - seconds vs hours. These terminate properly on the floor at the image of the window... not extending like the 'god beams' in the image I posted.

But - and OT now since this thread is about CR, but since you said you use Artlantis ... the Artlantis 5 'light cone' illuminates the inside surface of the jpeg. So, if I move the slider high enough to see a reasonable level of visible colored beams, then the window itself become solid white. I think this is a bug and will report to Abvent. Do you have 5?

Re: Visible lights - Caustics

Anonymous — Mon, 25 Aug 2014 09:37:40 GMT

Great thread guys!
I hope you don't mind me posting some post tricks to enhance/cheat some detailing.
If you can render passes in Cinerender you should render a lighting pass and then in photoshop add a little Radial Blur (Zoom Method) after that you can mess around with the blending modes. I think it will add alot to the scene.
And add a bit of chromatic aberation and noise (1%) to the whole scene.
Hope you get the desired result.
Cheers

edited : grammar