PDA

View Full Version : Dome Light Array



Filmdesigner
06-28-2006, 06:17 PM
I am building a Dome Lighting Array for use in some Archivis work. Some of the models I am building are pretty big and the Radiosity renders are taking many hours. I have built a test array in a hemisphere with about 124 lights, all at about 5% intensity.

My questions are;
1) I want to edit the lights collectively to get a nice gradient from horizontal to vertical intensity and camera relative colour shifts to mimic skydome lighting. I am doing this individually at the moment, which is a pain.
2) I also want to save the light array as an object or group. The only way I can do this at the moment is to save the Scene file and open it as a base file in all my new scenes.

This is a test render using the light array at the moment. It is missing a lot of details and BG landscaping, and the people suck. As you can see, the lighting is a bit hit-and-miss but there are some nice soft shadows forming.

I would appreciate any feedback.
Thanks.

jameswillmott
06-28-2006, 06:38 PM
Are you using spotlights or directionals?

I find that using fewer lights ( spots ) and using shadow maps with a high Fuzziness factor makes for lovely soft lighting.

Can't think of a quick way of editing the colours as you want, but with fewer spots the job isn't such a pain...

Filmdesigner
06-28-2006, 07:00 PM
I am using Spotlights. The fuzzyness is at 1 currently, as any more caused the shadows to "creep" under objects. You can see this if you look at the rendering I attached. The upper floor balcony roofs and louvre details have an effect of what could be sidelighting, but isn't. A bit weird, but still acceptible.

I neglected to mention I am using a single AREA light as the primarly light source and a single area light at about 25% intensity at about 25 meters under the camera to soften the shadows further. This I will fix with extra Array Lights in the next render. The lighting at this time of year in Australia is quite crisp, especially where this building going to be built.

Captain Obvious
06-29-2006, 12:25 AM
I would just like to point out that rendering with 124 directional lights with raytraced shadows will take about as long to render as backdrop radiosity with 6x18 samples. With well-tweaked settings and interpolated radiosity, you'll be able to render with two or three bounces of full global illumination faster than with a bunch of spotlights like that.

Or you can buy Fprime... :)

byte_fx
06-29-2006, 01:32 AM
1) I want to edit the lights collectively to get a nice gradient from horizontal to vertical intensity and camera relative colour shifts to mimic skydome lighting. I am doing this individually at the moment, which is a pain.

Wish there was a way.

All I can think of is to break the dome into vertical segments and use a different source light with the needed intensity and color for each band.

In theory you might be able to use something channel follower to reference a group of lights to a master. That would cut down on a bit on the manual editing. But I've never been able to get that to work.

If Newtek guys read this how about adding a gradient feature to light properties? If applied to the source light for a Luxigon array it could automatically adjust a light's color and intensity based on elevation.

[OT] A particle age gradient for Hypervoxel size wouldn't hurt either.

byte_fx

ingo
06-29-2006, 01:38 AM
124 lights are way to many. Just try out Eki's Overcaster Ambimage http://www.kolumbus.fi/erkki.halkka/plugpak/index.html , works well with only 24 lights.

starbase1
06-29-2006, 03:41 AM
Soft shadow mapped spotlights can be VERY good, but like you I have found problems with inaccurate shadows.

You can improve this situationn a LOT by:

1. Increasing the size of the shadow maps - the default is very small. (Though with this many in one scene you may hit momory problems). I have used 4k shadow maps for buildings before now.

2. Carefully adjust the size of the spotlight cone - I find this easiest to do by selecting the light as a viewpoint, and twidddling the cone angle until it only just covers the objects you need to light.

Hope that helps,
Nick

*Pete*
07-02-2006, 10:04 AM
Hey Filmdesigner.

where did you get those bushes from? did you make them self?

i would be very intrested to get them.

ingo
07-02-2006, 01:23 PM
Hey Pete, if you mean the odd hedges, DIY. Just use a UV-mapped polygon of a leaf and point-clone-plus to copy them.