topic Re: Visible sun light? in Visualization

Visible sun light?

Anonymous — Thu, 11 May 2023 09:40:18 GMT

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 😉

Re: Visible sun light?

fuzzytnth3 — Thu, 15 Sep 2016 16:38:11 GMT

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.

Re: Visible sun light?

Anonymous — Fri, 16 Sep 2016 08:20:16 GMT

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

Re: Visible sun light?

Anonymous — Fri, 16 Sep 2016 08:21:02 GMT

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

Re: Visible sun light?

Barry Kelly — Fri, 16 Sep 2016 08:56:15 GMT

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.

Re: Visible sun light?

Barry Kelly — Fri, 16 Sep 2016 09:03:12 GMT

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-caustics/

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

Barry.

Re: Visible sun light?

Erwin Edel — Fri, 16 Sep 2016 11:08:47 GMT

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-reference/tool-settings-dialog-boxes/special-lamp-parameters/general-light-sources-and-effects/

Re: Visible sun light?

Erwin Edel — Fri, 16 Sep 2016 11:31:50 GMT

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.

Re: Visible sun light?

Anonymous — Fri, 16 Sep 2016 11:46:23 GMT

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?

Re: Visible sun light?

Erwin Edel — Fri, 16 Sep 2016 11:54:48 GMT

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!

Re: Visible sun light?

Erwin Edel — Fri, 16 Sep 2016 11:57:14 GMT

Most default surfaces from ArchiCAD18 and later have caustic channel on by default, so unless you made stuff from scratch or are using an ArchiCAD17 or earlier project, it should work out of the box so to speak.

The image I show, has mostly 'white paint' as surface. Which is the one I checked before the render.

I don't generally go into these fancy render settings, go for a more sketchy look, so you've reached the pinnacle of my knowledge here, I'm afraid

Re: Visible sun light?

Anonymous — Fri, 16 Sep 2016 13:52:13 GMT

Erwin,

This is what I ended up with (see below). It definitely worked for my spotlight, unfortunately I closed the image after saving without making a note of the render time but I am going to try to replicate the sun using the general light as you have suggested and will post the results.

Re: Visible sun light?

Erwin Edel — Fri, 16 Sep 2016 14:09:29 GMT

From the artistic side of things, wouldn't you rather be trying to achieve this for your dark dungeons, mystical forest and old church renderings? I mean, even a simple google image search for volumetric light yields this as the typical result.

You don't really tend to get those beams of light in a brightly lit sunny afternoon living room render, right?

Or is all this just an excercise in seeing how the stuff works?

Re: Visible sun light?

Anonymous — Fri, 16 Sep 2016 15:06:46 GMT

Absolutely. So the below image is just my test scene anyway in case that wasn't clear. Actually having a spot light that has visible lights will be genuinely useful as we work on showrooms where night shots can be dramatized by having colour spots showing off products. We tend to have to add this in post-production (photoshop). The sun-light look I was partly hoping to learn from and have a up my sleep if I ever need it.

Re: Visible sun light?

Erwin Edel — Fri, 16 Sep 2016 15:11:20 GMT

Right, so try a lazy autumn afternoon mood for the room, you'll end up with better visible light, if the walls aren't as white, but rather a more subdued yellowy look?

You can probably play around with just two infinite general lights, rather than all the spotlights, to keep rendering times low. Chuck one inside, just to light up the whole place enough to see the interior reasonably and have the one outside a bit brighter to get a nice contrast and see the beams of light.