To make our image look nice, we are using the mr Photographic Exposure control. We will get to real caustics later, but for now it is looking pretty. And note how the background lighting changed in tone to match the environment? This is because Final Gathering is picking up the new environment and getting it's lighting from there:Īctually FG is even picking up some of the concentrated bright spots and creating a form of "faux caustics". This should give us something much more interesting to look at. In 3ds Max you do this by adding a Bitmap to your Environment slot, and make sure to set it to a spherical environment: (Note: When doing this you may need to play with the Physical Scale to avoid having the environment map render dark, see here) Some people may be tempted to cheat this with a bunch of specular only lights, but why cheat when there is a real reason for such effect - reflections of Bright Things.Īnd what's the easiest way to get some Bright Things, if not an HDR environment map? Lets slap in some interesting HDR environment map. Diamonds (like metals ) are not so interesting looking in-and-of themselves, but area all about reflections and very very bright "pings" of light. The scene is still looking rather dull with the gray background. This makes our transparency a bit "clearer": We need to fix that by setting it to IOR mode! However, by default it is not basing it on the index of refraction, but a custom curve. transparency is complete, but still "overridden" by reflections, and the reflections do depend on angle, just like on real dielectric materials. The automatic energy conservation of Arch&Design (mia_material) already makes this a decent looking transparent looking thing. Let us make it more gem-like by a) turning our diffuse to 0.0, We are using a default Arch&Design (mia_material) on the gems. So we add one of those to the scene, and very importantly, set it's option to "Use Scene Environment". This doesn't happen in 3ds Max unless we put in a "Skylight". In Maya and Softimage, the very act of doing this will implicitly light the scene from the environment. To do this we need turn on Final Gathering. Now these two arealights are not enough, we need indirect light, and to light the scene from the environment as well. This gives us the nice soft shadows and "soft" lighting that you would use for an artsy product render like this: We will be using the mr Photographic Exposure control, and we need to make sure to check the "Process Environment and Background" checkbox:Īlso make sure they are area lights. Since we are using photometric lights, this also requires us to use an exposure control. Make sure you aim the lights where they are needed - this is especially true with caustics. If we didn't give them a direction to shine, our photon emission phase would be much slower because so many photons would get lost in empty space. This is so we get the most efficient distribution of photons. That is a little bit more work to achieve in Maya or Softimage (XSI) because you have to set the photon energy up manually.Ī key point here is that we make them Target Lights (i.e. This will become especially important later when we get to the caustics, because the Photometric lights automatically gives us the proper photon energy for free. In 3ds Max the easiest way to do this is to use the Photometric lights. We really want to light this in the same way a real photographer would light his scene, with realistic lights with all their realistic effects. Especially we want to avoid nonphysical "hacks" like specular-only lights, lights without shadows, and other things. We need to follow physics as much as possible. Since I can't model worth crap, I downloaded a diamond cut according to the classic "round brilliant" from here, and made this supercomplex scene:įirst, make sure you have your gamma correction enabled, diamonds, like all physical things, should be rendered linearily. We start with a ridicolously simple 3D model. It is also coupled with the fact that the " cut " of a diamond is specifically made to enhance the "fire" (dispersion) and "brilliance" (ability to reflect light back to the viewer) as much as possible.īut even before we get to the actual dispersion part of things, lets try to see what it takes to render realistic gem's without it first. These stem from the fact that Diamond is a material with very high dispersion. One of the reasons is the characteristic property of fine diamonds known in the gem business as "fire" - the nice "pretty colors".
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