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Cafe Bar Visual

Posted: Mon May 16, 2011 7:55 pm
by johnvann
First time trial, any thoughts on the rendering. i have been looking at it for too long.

Re: Cafe Bar Visual

Posted: Tue May 17, 2011 6:18 am
by Pixero
That looks really good.

Re: Cafe Bar Visual

Posted: Tue May 17, 2011 2:56 pm
by daniel8742
It's good!!

Re: Cafe Bar Visual

Posted: Tue May 17, 2011 9:15 pm
by johnvann
Still struggling to get a slight reflection in the flooring, just to make it look like it is polished. Same issue with some chrome details I would like to add in.

Re: Cafe Bar Visual

Posted: Tue May 17, 2011 10:50 pm
by AdamB
Hi John,

Place an IrrCache in the center of the room to capture the light and set the floor material to specular=0.2, roughness=0.4
Check the box next to Fresnel Color and bring down the brightness and tweak the IOR so the Fresnel comes in more slowly.

(excuse the totally out of scale texturing, but hopefully this gives you the idea)
SketchUpScreenSnapz096.png
SketchUpScreenSnapz096.png (242.94 KiB) Viewed 6449 times

Re: Cafe Bar Visual

Posted: Wed May 18, 2011 6:25 pm
by johnvann
Thanks for the advice, though not meaning to be dense, what is an irrcache?

Re: Cafe Bar Visual

Posted: Wed May 18, 2011 6:49 pm
by AdamB
johnvann wrote:Thanks for the advice, though not meaning to be dense, what is an irrcache?
:lol:
You're not alone, believe me.

Exact reflections require one to trace the path of light for every pixel to find out where it came from. This is is called "Raytracing" and is generally pretty slow (certainly not at 30Hz on your PC) but you do get an exact result.

LightUp uses a technique whereby the light from all directions at 1 position is captured. This "Irradiance Cache" aka IrrCache is then used to approximate the reflections for all surfaces nearby. So the reflections are exact only when the camera is in precisely the same position as the IrrCache when it captured in the incoming light. As the camera moves away from that point, the reflections will be more distorted.

So LightUp - in common with all realtime graphics systems - uses these caches to give fast realtime reflections that give a good impression of shiny surfaces. Mostly this technique gives a good trade-off between performance and accuracy. However, it is easy to setup reflections where what you see reflected is not what you might expect, so there is some skill in placing these IrrCache around your model to capture light.

LightUp uses the nearest IrrCache it can find for reflections (or the skybox if it can find none), so if you have a shiny espresso machine in the corner, its worth sticking an IrrCache closeby so it captures the light in that locale.

Adam