I’m currently working on a project which would show an hourglass with colored water dripping down. I haven’t even reached the part where the FluidSim kicks in, and I’m already pulling my hair out over the rendering of just the hourglass + liquid…
Here is the .blend file so you can have an idea of what I’m talking about.
I have tried to render with three different engines: BI, Yafray and Indigo, and I’m not at all satisfied with the results. Rendering with Indigo was purely out of curiosity anyway, as I plan to animate the fluid and I don’t intend on having my computer tied up for a year to render some 250 frames.
The problem I encounter is twofold…
First, I can’t seem to get properly transparent glass and/or liquid. I searched the Internet and found this came from the RayDepth setting which wasn’t high enough. I did crank it up but it resulted in CRAZY render times (something like 4 hours for ONE still with BI…) If it takes that long, I don’t really see the point of NOT using an photorealistic unbiased renderer (such as Indigo…) Because even with such lengthy render times, it still doesn’t look good (here is a previous version rendered with BI, which is nowhere close to photorealistic: http://rapidshare.com/files/78541149/BlenderInternal.jpg.html) Yafray doesn’t even correctly render: the liquid seems to fill the whole bottom part of the hourglass (it acts like the glass’s refraction index is way off the mark; it looks like solid glass with a red thing inside rather than hollow glass with liquid inside.)
My second problem was that, after adding a ground plane (which I removed in this version of the .blend file), I didn’t get any caustics, but an opaque shadow, which is very unlikely. I checked out the Yafray Caustics tutorial, and tried rendering with the indicating GI settings. I waited another 4 hours (!) only to find that there were no caustics whatsoever and, what’s more, the liquid did not render at all (most likely because I hadn’t cranked up the Yafray panel’s RayDepth setting, only the Depth and CDepth in the GI panel…) Plus they mention Photon lamps and whatnot, and I don’t understand a thing to all their gibberish. Clearly not noob-accessible!
I’m growing quite desperate here, so any kind of help would be most welcome… My computer does not seem so outdated to me (Core2Duo 3 GHz with 2 GB RAM) and I can’t seem to be able to render those damn three objects correctly in an acceptable amount of time. I’m very new to Blender and CG in general, and am well aware that rendering glass and liquids in the first place is definitely not the easiest thing, but I know that I can reuse the hourglass thing for a project with my students next year, so I figured it would be nicer to work on some concrete project, and not waste time on random tests.
To finish, if there is no way to render the scene satisfactorily with BI or Rafray, I’d be prepared to render with Indigo (maybe I can get the network administrator @ school to turn the computer room into a render farm for me, during vacation for example…) but then again, I run into some similar rendering problems: the liquid does not show through the glass when I render (the body of the hourglass is simply gray and opaque). I followed every modelling directions (liquid overlapping the glass before spinning the curve, modelling meniscus and what have you) and material instructions from the Indigo documentation, even tried to crank up the Max Depth and Max. num. consec. reject settings, took care to assign a greater precedence to the glass material than to the liquid, because glass displaces water, etc. Still, it won’t work.
I know I’m doing something (very possibly MANY things) wrong, but I’m kinda stuck in place.
Any help would be greatly appreciated. Thanks,