It has long been accepted that the Bryce ray trace render engine does not have caustic reflections. You can see a reflection in (on) the surface of a mirror, but light will not 'bounce' off of the mirror surface and land on another surface (indeed, light won't bounce off of any surface). Bryce5 introduced a new render feature called "True Ambience". It has been met largely with disdain from users. It isn't particularly realistic (so far) and use of it can result in punishing render times. Not long after Bryce5 came out I started fiddling with True Ambience. I was intrigued with the notion of surfaces giving off light (as opposed to points, as with regular Bryce lights), and I started looking for alternative techniques to multi light arrays to provide soft lighting. Although I was able to come up with a workable soft light system, it wouldn't work with imported meshes (the polygons would not smooth) and the render times became as bad as with light arrays. It was interesting, but not much use. More recently I noticed something in a True Ambience soft light render I was doing that surprised me and intrigued me even more. I found that mirrored surfaces appeared to bounce the light (from a light emitting surface) onto other surfaces. This isn't supposed to happen - these are caustic reflections and Bryce does not have those. This means that true ambient light isn't just "a glow that is applied to other ambient surfaces based on the shape of the emitting object and the squared fall off of brightness with distance". The light coming from surfaces in True Ambience is actual virtual rays/photons that have optical properties. These properties are limited, but in some ways they are more realistic than the properties of Bryce's normal raytracing lights. There will follow (lousy internet connection permitting) a series of pictures illustrating these properties. This isn't the 'useful and practical' application of True Ambience I mentioned in another thread yesterday, it's just more bizarre fiddling at the edge of one of Bryce's frontiers that is mildly interesting. It is to me, anyway. ;-)

I'd say fire away with those 'mildly interesting' effects. I think TA is very interesting :)

OK, on the left we have a surface of the giving forth of the light. There isn't any other light falling on the scene, which is why you can't see the black cat in the background (that's a sort of joke). The big ball has the same simple grey material as the ground plane. The two smaller balls share the same simple mirror material (just reflection - nothing else) which is also applied to the flat mirror at the back. As you can see, the light coming from the bright surface is interupted in its path by objects - in other words it casts shadows. This is an optical property. They're nice soft shadows, since the light source is the diffuse sort that set me searching all those months back. I hope it also plainly evident that the light is being bounced back into the scene from the mirror at the back. Closer examination will reveal the little curvy caustic reflections given off by the small spheres.

Connecting to Renderosity tonight (most nights) is about as pleasant as wire brushing the insides of my eyelids. This apple pancake and ice cream is almost taking my mind off the pain, though.

Did I mention closer examination? Oooh, look at all the little caustics. In this zoomed view, you can see that light is bouncing off the big mirror, hitting the mirrored balls and then landing on the other surfaces. This isn't just caustics - we've got physics going on here. There is one odd thing happening. The big ball has what looks like a blurry reflection of the light-source-surface. But the ball material has no reflective properties (you can't see any other reflections in it) and blurry reflections is not set in the render options. Shrug. Other weird stuff happens in the True Ambience universe, as we'll see in a bit.

I'm through with this. No, I'm not giving up, I just thought it might be nice to look at transmissions instead of reflections. A slightly altered scene. The big ball is now a round lump of glass. As you can see, True Ambience light can also be refracted. I've placed a colourful pole behind the glass ball to help show its optical properties. Those optics are focussing the light. You could make a magnifying glass and torment a virtual ant colony with this (if only there could be more light). When I first did this scene, it looked weird. It was like the glass ball was reflecting as well and refracting. But it didn't have any reflective properties in its material! So I disabled reflections in the optics section of the render properties dialog and it turned out OK. You'll see the weirdness later.

We're back in Kansas with this one. I just wanted to show that the glass ball would not refract the light from the light-source-surface in a normal render - that trick is for the True Ambience universe. The scene is otherwise the same, except the sun is enabled (I had to do that so's you could actually see things). I've placed an object to cast a shadow behind the ball, in case anyone thought there might be some refracted light that was being washed out by the sunlight. The glass is refracting the sun OK. Bryce has always had caustics of some sort since its first inception. Nothing happening here. Move along.

Can you send the first scene to me at aldaron@charter.net? I can't seem to reproduce it exactly like your's and would like to see what I'm doing different. Thanks

*--gasp-- the connection tonight is truly shite* Sometimes, when you want it all, you get more than you want. I wanted to put a mirror behind the glass ball, just to show off. It would mean that the light would be refracted through the ball, hit the mirror and land on the ground (which might be sufficient to elicit a "dude" from AgentSmith). Well, check it out. Bend and bounce, baby. Problem was, to do that I had to enable reflections again - which meant the non-reflective reflectance would come back to haunt. So there before you, you can see a bit of the wild side of True Ambience-ville. Here you can have an apparently 100 percent reflective surface that also lets all the light through! I don't think we're in Kansas anymore...

This is facinating, I wish you'd do a proper tutorial to enlighten us simple minded folk, ie. me...........lol 8) Catlin

kick ass man! I always new bryce was more powerful than thought.

Wow! this is impressive! :)

GOod stuff, PJF! Those are all great examples of what Bryce can do...

Thank you! This is really great and I cast my vote for a tutorial from scratch also. :-) I love it when I learn new ways of doing things in Bryce. Damsel

My apologies for disappearing. Connections became impossible last night and I've been really busy on other things today (pesky real life). Connections have been crap today, too (half an hour to get this through after writing). I think it may be my cable ISP. It may be time to move over to ADSL. I will be writing a tutorial, though probably not on this specific setup. This is bizarre fiddling in one dark corner of True Ambience that doesn't really have any practical application. I have merely been pursuing my feeling that ambient-light in True Ambience has optical properties. The tutorial will be on how True Ambience is the best Bryce thing since sliced bread, so long as you're not a Poser figure.

Just one to cap it off. You're now in a top view, looking down onto the light-source-surface. In front of that has been placed a set of boxes in various shapes and sizes, all of which have mirrored surfaces. The point of the positioning of the boxes is to stop light from the light-source-surface shining directly outside of the group. The only way out for the light is by reflection of reflection of reflection... (image has had brightness and contrast boosted to show the effect more clearly)

It's pretty clear that it has been reflected round the corners. 8)

GOddamn ridiculous work, PJF! I love the arrows, too, they are better than mine! (grins)

wow!

heres my stab at it.What am I doing different from you?Can you share the settings you used on the sky,objects,ambient light,and ground plane.I couldnt get it to work right.the light only showed up when the ground was ambient.But then it looked like this pic i uploaded.how do you get those shadows?

unityboxer, you're nearly there with your scene. Make the ambient level for the ground and ball much darker (I use the colour picker rather than the slider as it gives more control). To compensate for the darkness, you need more light. Select your ambient-light-source-surface and set reflection and transparency to 100 (as well as max ambience). This will increase the render times. You can also replicate the ambient-light-source-surface and stack them (I think you have to move each one slightly off axis from the rest, and this might not work with the reflection set to max (no time to fiddle at the moment). But hey, you can already see the caustics in yours as it is.

This is some great work PJF! Thanks for taking the time.

I haven't had a play with the settings yet but I think I will later. I just love the way you have proved that reflection does happen in Bryce. Lighting in Bryce is always a trial but the more we learn about it's properties the easier it should get. Thanks PJF. 8) Catlin