Visible sun light?

[Anonymous]

Hi all,

Is it possible to tweak cinerender so that sun light rays are actually visible in the render? Thinking of how trying to recreate the kind of look you might get where light hits dust (would I use the fog setting for this?)

Many thanks from a novice trying to become an expert 😉

[fuzzytnth3]

Ah good old crepuscular rays.

I've used Strata Design 3d to get this effect using spotlights that have a fog setting within the light source. I assume Cinerender has a similar capability

But I think I would actually do this in Photoshop as I found getting it to look right in the 3d model rendering was fiddly.

Edit...

I just checked the General Lights in ArchiCAD have a "Noisy Light" setting which looks like it will let you get what you are after.

[Anonymous]

Thank you for your reply. Unfortunately, I haven't got it working yet, I'm wondering if something in the actual Cinerender settings is overriding the light? I'll have a dig around but this is what I got so far see below

[Anonymous]

Heres the lamp settings (for purple spotlight which you can just about see illuminating part of the floor).

[Barry Kelly]

Have a look at 'Caustics" in the reference guide.

You will need to set this up in your lamps but don't forget to set it on in the render settings as well.

Barry.

[Barry Kelly]

There is also a short movie although this is more about caustics in water.

http://helpcenter.graphisoft.com/videos/archicad/documenting/rendering/archicad18-new-features-caust...

I see at the end there is a setting for surface caustics as well as volume caustics in the cinerender settings.

Barry.

[Erwin Edel]

I think the settings you are looking for is Visible Light rather (aka volumetric light / god rays)?

A few of the lightsources offer it, such as the General Light and the spotlights.

http://helpcenter.graphisoft.com/guides/archicad-18/archicad-18-int-reference-guide/user-interface-r...

[Erwin Edel]

I did a quick test.

Drop a general light with infinite strength outside, a little up in the air from your window, aim it (it has arrow with hotspot in 3D) at your window. Do not use the sunlight in cinerender, on Lights.

Turn on visible light and noise in the light settings.

Turn on caustics in cinerender.

Make sure the surfaces you are using have the caustic channel turned on too.

Below is the result. I didn't fine tune yet with colours etc. but you can see a little bit the rays of light.

[Anonymous]

Barry & Erwin and others thankyou.

I am just running a test render of my own at the moment to see if I have managed to get it running correctly on a spot light. Quite interesting the difference it has had on render time (previously a scene was taking around about 1 minute start to finish) so far I am on 38% calculating GI and already 24 minutes in.

Erwin, just to be clear are you saying that I do not use sunlight at all? And recreated a sun light affect using a general light? When you say about having caustics turned on for surfaces, in your example is the window glass the only really important one to get the effect?

[Erwin Edel]

I used the general light, it is more basic as it were than the spotlights, so render times aren't that dramatic. Still a lot more than not having the fancy smancy things.

It's a ball of light basically, it will be very tricky to replicate the excact angle of your sun, so I would just turn it off and have this behave as 'sun'.

One fake computer generated 'sun' is as good as the other 😉.

Do some test renders at lower settings, before settling on a final render and coffee break!