Re: VRay 1.5 SP3 - VRayEnvironmentFog Tutorial - Caustics [ENG]
This short tutorial shows steps to obtain green shpere rendering.
Run 3ds max and set scene in cm, that will help us in understanding caustics setting units.Fig. 03 - File units.
Now create scene elements: Plane, Standard camera, Geosphere and Spotlight.Fig. 04 - Four elements in our test. Look at large plane size.
The "rock" is a dense geosphere with Noise modifier on.Fig. 05 - Deformed Geosphere params.
Camera is a simple 3ds max Standard, while light is a slight modified Spot.Fig. 06 - Changed Spot light params.
We won't use Global Illumination
in this test, because we just need to understand how getting volume caustics. Adding GI
will waste time. though not strictely necessary, set LWF
here too.Fig. 07 - Setting panels.
As we can see, many setting has been left as default. Main stands in caustics. Following settings in study scene.Fig. 08 - Photon Map settings.
A quick explanation to simple params. You can find a caustics videotutorial here
: as standard light multiplier, increases or decreases caustics intensity. Makes them lighter, brighter. Modifying value won't request new PM
calculation. In fact, once computed, it can be stored and used again, just like happens with IM
. to achieve physically correct results use 1, but feel free to change it.Max density
: figure Max density
as a grid size. Lesser the value, denser the grid; we'll get better quality spending more photons for "clean" caustics. Smilar to radiosity rule, with high-divided meshes we get precise solution at cost of time.Search distance
: setted grid size, VRay
computes and interpolates photons. Higher search distance
value means more photons in interpolation algorithm; giving blurred caustic with definition loss.Max photons
: maximum photon number VRay
uses to blur PM
. If Search distance
uses distance among photons, Max photons
uses their number. Both can be modified without new PM
Last important parameter for PM
generating, physically defines photon number VRay
uses in PM
estimating. Since photon emitter is light based, last param is in VRay light properties.Fig. 09 - Reach this panel following V-Ray properties, clicking right on selected Spot light. We use 2.000^2 photons.
Run render on a DualXeon Quadcore 3.2 ghz.Fig. 10 - We get caustics in 9 seconds + 30 for PM.
).Fig. 11 - The volume effect.
See both volume light cone and volume caustics in render.Fig. 12 - Last rendering, got in 59 secs + 30 for PM, necessary in VEF's checked.
If you want, you can use hidden VRay feature with maxscript:renderers.current.caustics_showCalcPhase=false
In order to run progressive and high-precise caustics computation. A deeper explanation in my videotutorial
Same rendering needing 12 minutes. First rendering shows pure volume caustics (reported timing is wrong), second final rendering.Fig. 13 - Final rendering with progressive caustics.
Resulting caustics are very precise, but cause higher noise. rule is quite similar to PM
Hope you are enjoy with my little tutorial. In attachment the video.
See the next time