Anyhow, here goes...

I'm experimenting with rendering the above product image in Bryce and would like to create the effect of light shining through the water and onto the concrete pipe bellow its surface. My intent is to create the caustic lighting pattern that should appear on the concrete pipe under the water's surface. Did that make sense? I hope so.

Has anyone tried to do something similar?

I'm well aware that such caustic effects are usually created in Bryce with a pattern of an actual water caustic used as a gel to filter a light. Although I've never actually tried it myself yet. I've read tutorials for doing just this in underwater scenes. I just haven't seen it done for an "above water" scene.

If I use the same method with the scene above it seems to me that I would have to complete one redering with the caustics and one without, and the edit the two together. The reason I see for this is that the light with the gel would be casting the caustic pattern on more then the area under the water.

The other option I can see is to make the that part of the storm drain pipe which is underwater a separate object and apply a custom material to it... a material which has been made to look like the caustic effect. But... damn, I would have to contend with recreating the layer of dirt at the bottom of the pipe in some other way or make it part of the material (or texture map)also.

If anyone has a better solution please let me know. Thanks!

Oh... If there is anything in the image above that you think needs improvement don't restrain yourself and please tell me. :) I still have a lot to learn about Bryce.

Wow...i really like it, i have absolutely no idea what you want done, but i know much less than you do. Sorry i can't help out.

OK .... first, I'm not certain why you want to produce caustics since this is a cutaway view. In point of fact, the light would not actually be reaching the water. But, leaving that for a moment, most of the time that I have done caustics, I have had to composite the image because the lighting from the caustics interefered with some of the other lighting effects - slowing rendering times to something geological. So, since I've done the composite route many times now, that's probably the route I would take in your situation.

Since Brice 5 still cannot do caustics internaly, it is almost impossible to do it, unless you define your water as a very complicated and hard to achieve volumetric texture, with density behavior according to a already pre-made caustics 2d texture... Better results, and i tried it b4, can be done by compositing 2 different images, one which you already have, and another one, with aditional source of light, or even the same one (whichever gives better results) rendered with the pipe and water only mask ! :) Hope this helped any !!! :) Regards.

Thanks. Glad you like the image. :) Caustics are envelopes of rays (light rays) eminating from a point (a light source) and reflected or refracted by a curved surface (water surface riples in this case). So, the caustic effect I'm after is caused by light refracting unevenly when it passes through the surface of the water in my image. Takke a look at the little image above as an example of the caustic effect I'm talking about (image borrowed from Linda Ewing's tutorial "Deep Sea Diving with Bryce"). See how there are squigly areas of greater light intensity cast on the sea floor? That's the caustic effect I'm talking about which is caused by light defracting through the rippled surface of the water.

rickymaveety,

Are you saying the light would not reach the water because it wouldn't be passing through the ground even though you can't see the ground because this is a cutawy view? :) Well... I'm taking the view that the ground really is cutaway and not there or invisible, and that the light can reach the water. In anycase, the light is reaching the water in the storm drain pipe in the image, or at least the part of the water not in shadow. Does that make sense. I hope I understood what you were trying to say correctly.

Kemal & rickmaveety,

Thank you for confirming the notion that it would be best to create two separate renders, one with and one without the caustics, and to edit them together.

 
If anyone else has any comments or ideas please don't hesitate to post them.  
 
Thanks!

Alan, you say you still have a lot to learn about Bryce but it is obvious that you have learned a lot ALREADY! Either that or you apparently have some other advanced modeling skills from other applications. I like your cutaway. Very precise and yet has some nice extra touches that really adds to the appeal (ie, the little pieces of dirt & gravel). I vote for the technique of the two separate renders. That would be the simplest to achieve I would think and in the business world the quicker route is more money in the bank as long as the result is as desired.

Well your work is amazing! A lot of details that give a fancy look to the image. I agree with my colleagues the two render method is the best. Cheers

As good or better already than the commercial work in industrial design graphics that I've seen.

Using light gels can get caustic effects decent enough, here's a few tests to show that Bryce can do it: http://claygraphics.phase2.net/Aquatic.html and http://claygraphics.phase2.net/fillingpool2.mov you'll need the latest quicktime to view them.

zescanner, :)... I'll admit to being partially guilty to having advanced modeling skills from other applications. I'm trained in traditional media but I'm making the transistion to digital media, or should I say... adding it to my repertoire. I'm a Lightwave 3D user (admittedly a new Lightwave user at that) and and Rhino 3D user. I've also dabbled with a few other 3D programs such as Hash Animation Master. As far as Bryce goes I still don't have the materials lab or deep texture editor completely figured out and there are some tools like the meta balls I haven't even touched yet. There is a depth/possibility to a lot of the tools that I've only begun to explore. (Damn, do I really need to sleep... well, I'd miss creative resource in dreaming I suppose.) Some of the objects in the image I posted above were created in Rhinoceros 3D and imported into Bryce.

Clay, Thanks for those links. Those are some nice little animations you created.

Alan, off the top of my head, you might put a light into the water and then try playing with the bump of the water. Possibly a parallel light or a spotlight. Point it towards the wall then. Other way would be, as in that tutorial, to put a light above the water, point it towards the wall of the sewer and then put a gel on the light. Clouds or Difference Clouds (and then blurred) in Photoshop would serve well as the gel. It might be a faster way. I'd have to try. Nicely modelled. Rhino, I suppose? :-) BTW, why the oil looks like it's floating? Kemal, apropos the internal caustics, I'm not certain what you mean. Take a look at When the Music's Over in my gallery. There's nothing between the lights and the caustic pattern except the glass of the lamp.

Uh, now that I read your post more closely and saw that you want the caustic pattern to be on the bottom of the sewer. Edit my previous post and remove that part "point it towards the wall". I thought you wanted a reflection on the wall. Other stuff still stands, just put a light above the water, point it down. Try with gel and without it. You might want to increase TIR in Render options. Also, range, intensity and colour will also play a role in how the caustics look.

What a great cutaway.

Erlik,

Actually, I do wish to add caustic reflections to the wall of the pipe above the water as well. I'm also thinking about adding some caustic effects to all the other water sources in the image. So, your advice is helpful in both regards. Thanks.

I'm using Caustics Generator v1.3 to create the caustic gel pattern and editting it in Photoshop. (http://www.lysator.liu.se/~kand/caustics/).

Placing the caustics gel on a scaled up cube light above the scene, with cast shadows turned off on the light, seems to be working quite well. It is not only creating the caustics bellow the water, but also the caustics on the walls of the pipe, which could be viewed as the reflections off the water. I'll post an image later today with the caustics added.

The product, storm drain pipes, curb, pavement, and flat planes that represent the cut-away dirt were all modeled in Rhino. Everthing else was done in Bryce. All the details and stones added to the dirt were accomplished with terrains and a few stone objects. The grass is also done with terrains.

Floating Oil... Do you mean the oil stains on the pavement. (There isn't any other oil in the image) If you think there is, please let me know. Darn, I was hoping that the floating effect wasn't too noticable. :) The only way I could think to quickly create the oil stains was to copy and past the pavement three times and raise each copy by 0.01 Bryce units. A different transparent oil stain material was then applied to each copy of the pavement. Unfortunately this tended to make the oil look like it was floating. I think the .jpg compression might also have enhanced the floating look.

 
GROINGRINDER,  
 
Thanks for the compliment. :)

Yep, that oil stain. Why don't you create an oil stain with metaballs? It will take time, it will probably increase render time, but it will certainly look better. Just flatten them to ... 0.1 BU or so, and then put them so the upper half is above the pavement surface. Copy and change X-Z dimensions to taste. Even the part that flows down into drain can be easily done with metaballs. And possibly you might get that oil/water effect in the drain. Now I'm already hairsplitting, the grille doesn't have a noticeable shadow. Which would be a pity to remain. It's a great model and especially the textures.

Erlik, Hairsplitting, nit-picing, etc. is what I'm after. :) Let me have it with both barrels! Thanks for the idea on using metaballs. The seeming lack of a shadow for the grille has bothered me as well. I had a difficult time finding a lighting setup that cast pleasing shadows for the entire scene and as a result the shadow for the grille has suffered. I'll see what I can do to fix it.

Aye, Alan, I think you had the right of it in the first post. Only, add one... To me, this one screams multi-pass render. One as it is in your first post, one with the caustic gel (maybe just plop-render it, for the sake of speed...) and finally one for the grill's shadows. If you are used to Lightwave and Rhino, I'm guessing you are probably used to Photoshop, and compositing those three should be cake for ya! Also, with these three renders, you'll have much more control of course over how much caustic-glow you want, and how deep the shadows will be for the grill.

Just to add my two cents, i immediately thought of a rectangular parallel light fitted to the size of the drain and enhanced with a caustics gel. Sounds like you're finding something that works for ya. Nice work all around!

Also i don't think you and Erlik are understanding each other. He's saying that what's pouring into the filter looks like oil. I agree. I think you're referring to something else as being the oil "stain". The metaballs are being suggested for the liquid so it doesn't look like it's floating.

Note that Alan said "oil stain on the pavement". The green liquid that flows towards the drain, as I understand it.

When are we going to see the current version of this wonderful WIP?

zescanner, The updated image is coming... its just taking longer to render and tweak then I expected, even though I'm using plop-renders. :) [I suppose it doesn't help that I'm working on multple projects at once.] Erlik & bigbadelf, OK, yes, we misunderstood each other about the "oil stain". Erlik, are you refering to the darkening of the pavement around the green water as well as the green water itself? I do agree that this looks odd. It was my poor attempt at trying to make the pavement/concrete look wet along the edge of the water. Even though the croncrete is painted yellow, I was trying to simulate the effect of the water soaking into the concrete. I think the really big problem is that I made the water much to thick. For speed I modeled the water in Rhino, but since I've never tried to illustrate water in this way I'm still learning and figuring out how best to do it. Next time I'll have to use meta-balls for the water. In the meantime I'll try sinking the water object further into the concrete and pavement. Back to work...

Ohhh... shadowdragonlord, Thanks for your comments. Yes, this one does scream multipass renders. ;) The image I posted uses three separate renders already, which I editted together in Photoshop. Looks like the final image may use up to 5 separate renders.

you could make the drain pipe semitransparant and light it from the bottom with a light with procedural gel and restricted length so it only covers the parts you want.

No, I meant the green water itself. Er, if it's oil, it's too much viscous to sink into the concrete, ain't it?

Erlik, It's supposed to be water with mud and what could be green anti-freeze mixed in. In the large render (much too large to post) its possible to see the mud/silt layer in the water, but it gets lost in the compressed and smaller jpg. There isn't supposed to be any oil in the image other then the random dark stains on the concrete and asphalt. (Oil isn't usually green is it? I've never seen green oil myself.) When you first refered to the green water as oil I think this is what confused me since I don't see it as being oil in any way shape or form. Everyone sees things a little different. That's part of the reason for me seeking feed-back on the image. ;) ...get some other view points. ysvry, That's an idea... I'll have to try lighting the storm drain pipe that way in a test image.

Ah, that's different then. As to the oil, I think there is some kind of green oil here. Or maybe I'm just conflating it with antifreeze, which is also thicker than water and slightly oily looking.

Update posted here.