Beginners Question: Watery Scene

[Peoples]

Have you read the caustics tutorial on maxon's site? It has a fishtank with sand at the bottom and the shadows/caustics are very nicely visible. I suggest you try that one:thumbsup:

[TheLegend299]

You need to use alphas to get the shadow on the bottom of the pool (It'll work but I'm sure theres a better way) I'll take a look for ya good look:p .

[Per-Anders]

ah... the carrara scene to which you refer used i think either textures on the tiles or on the light to give the effect.

caustics will do the trick for you. what you should do is make a spotlight that points at thescene from teh same point as your main sunlight light. then keeping the spotlight selected if you go to your viewport menu and go to Cameras->Link Active Object you should be looking through the light. what you should now do is use the move rotate tool in the top right of the viewport to bring your swimming pool into view, and then you need to change some of teh lights parameters

on the details page in the attributes manager (make sure you've got your spotlight selected) change the outer radius so that the outside circle just covers the pool or the area that you want caustics to happen in. you can also click and drag the dots on teh circle to change the radius interactively. once you've got that you will want the inner radius to be equal to the outer radius (as you don't want any falloff). switch on "No Diffuse" and "No Specular" as we don't want this spotlight to actually cast any real light into the scene... just caustics.

next go to the caustics tab of the light. enable surface caustics, and probably bring the energy level up o about 200%. the photons level is probably oik for the moment as we just want to get teh brightness of the caustics right first, then we can come back and add more potons to make the caustics smoother and less "dotty" once we get that sorted.

now go to the render setings dialog box and in there under caustics you will have to enable caustics again, so make sure that surface caustics are enables, and because you're likely to be making some tweaks don't forget to make the Recompute "Always" (you can change that to never or first time lter on when you're happy with the caustics, then you wont hav to wait so long for each render to begin).

to make the caustics work well add your water material to the pool water surace. give it a good bump map, and nice and translucent with a good inder of refraction (ior) of between 1.37 and 1.4 (water). then you might want a little bit of reflection. to get a good reflection put a BhodiNUT Fresnel into the reflection channel, this makes the material more reflective at sharper angles to the camera, you can play around with the gradient if you want. white being more reflective, black being less so. then up the specualar level a lot till you get something looking more like water.

this should get you started at least with caustics. once you render that looking through the pool surface you should see the "shadows" a little bit more. if youw ant to make the shadows stronger still then you cal always use a displacement map on the pools surface (make sure that the geometry for the water surface is subdivided plenty before doing this as it changes the actual geometry for rendering.. i.e. a single poly might just have one point raised even though you've got a detailed displacement map, the more polys there are the more like the original texture the displacement will be), and then making the lights cast shadows.

anyhow hope that some of these techniques help a little. once you've got the caustics looking nice and bright endough you can up the number of photons in the light's settings. i generally just add another 0 to the end of the number, but you can fine tune it however you want till you get nice smooth reflected light.

[FusionDG]

Sadie,

Great explanation!

When is your C4D R8 book coming out? :shrug:

You explain things so thoroughly and yet in laymans terms I would buy any book you wrote on C4D in a heartbeat! :thumbsup:

[Per-Anders]

well i'd write a book if i hought i could find a publisher and if i had any idea about what the content should be... as it is i think i'll settle for just oding teh odd tutorial on my website and the occasional bit of advice out here on the forums. but thanks for the vote of confidence :beer:

[Wigwam]

Wow Sadie,

Thanx for all the info!:thumbsup:

I'll be having a go later. In the meantime I tried the Maxon Caustics tutorial with the "fishtank."
I noticed something strange: is the size of the water cube and its position correct in the tutorial?
Setting it up as it is detailed in the toot, I don't see the sand. I assuems I had to ensure the water cube lies on the sand cube or intersects it. That way I get the sand to be seen, otherwise I get the wavy surface showing o nthe bottom of the water cube.
Also, I notice that when rendering a scene that shows the view through the side of the glass tank (at a slightly oblique angle, so that I can see the sand still) the sand is distorted as though I were looking through the surtface of the water. This is probably the effect of the texture on the side of the water cube. In real life Iwould expect to see an undistorted view. How can I do this.
I've been trying to just put the water texture on the top of the water cube but can't figure out how to do this.

Finally, I set up an animated camera that looped up and over the tank so that we ended up looking straicht down onto the fishtank sand. It was just under 3-seconds in length and took 3 1/2 hours to render to 320by240 avi!:annoyed:
I think I need a faster PC (PIII 750MHz with 364M RAM...is what I have at the moment.):D

[CGTalk Moderation]

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.