Jeff Patton JeffPatton Location: Lexington, USA Language(s):
English Member Since: August 2002 Last Updated: 14 November 2009 Portfolio Views: 1069055 Chosen as Favorite: 521
I just had a small breaktrough with my plush material using a fresnel falloff map in the diffuse map.
I'm making a realistic interior and I have a quick question about white balance. I have a room with one light in the ceiling, 3000K, and a window on one wall to allow bounced sun- & skylight into the scene. I'm unsure where to put my whitepoint.
I can easily adjust it to something I like (have it at 5000K now - gives me a nice blue light from the sky, but also a warm glow from the ceiling light), but I'm wondering if there's a "correct" setting for the whitepoint in such a scene? By correct I mean what maybe a photographer would use if he were to take pictures of the interior or what our eyes would see if we were standing in the room.
Good question. I'm just getting started in the world of photography so I'm not sure if there's a rule of thumb for that scenario. I'd think that would lead into a gray area where it comes down to artist preference...but who knows, maybe there is a guideline. As time allows I'll keep digging through some photography websites/books and see if I can find a rule for that scenario.
And for what it's worth (and reference) my digital camera has these presets:
Daylight = 5200k
Shade = 7000k
Cloudy = 6000k
Tungsten = 3200k
White Fluorescent light = 4000k
AWB (auto)
Flash
Custom
hi jeff, i've just been experimenting with caustics in your kelvin temp example scene, where you have two sky portals acting as visible area lights. is there anyway of incoporating hdri into this scene. the only way i know of using hdri so far is by adding a hdr image to the environment map slot, then instancing this into the material editor (changing a few settings along the way) and then instancing this into the sky colour of a skylight. so can hdr be incorporated into the scene with the sky portals rather than a skylight???
sorry jeff, my bad, i've done it now, i was being really really slow
i just used exactly the same process as the skylight, but skipped the bit for where i instance the map into the skylight 'sky colour slot'. i also unchecked visible to renderer on the sky portals and it seems to work fine
sorry just been playing with MR lots today, however, i have come across a problem when trying to animate an objects visibility.
i want a gradual transition from completely invisible to fully opaque.
however i believe mental ray doesn't support object visibility.
is there a workaround for this
i have attempted the effect with a blend material and then animating the mix amount from 0 to 100. this works on the object, however i am still gettin shadows when the object is completely invisible.
i am going to try one more thing and that is to animate the 'cutout' slot in an arch and design material from a solid black colour to a white colour via the use of a gradient, hopefully this will work.
if you think of any workarounds then please let me know
Right, the visibility track can't be animated with mental ray (it's either on or off). It's a common complaint and believe me when I say that Autodesk is aware of this issue. The only way around it that I know is to do exactly what you're doing...animate materials locally.
thanks for the response jeff, i have rendered out two animations, one is using standard materials and animating the mix amount on the blend materials. The other is the same process on ana arch and design material and animating from black to white in the cutout slot.
both animations have the same problem, and the area where the object (teapot in this case) lies on the ground plane, is still visible when the teapot is meant to be fully invisible.
is there somewhere i could upload these animations too so that you could take a look at what i mean???
i will try and upload them to my blog and create a blog entry detailing what i've done and errors that have occurred (i guess this would be useful for others as traffic starts to hit my blog
Just a guess, but it sounds like you may be trying to use a save final gather map or possibly ambient occlusion in your tests. I tried a simple setup as you describe with using the cutout map of an A&D material and encountered no problems: http://jeffpatton.net/Temp/visibility_test.mov
Final Gather is view dependent, so if anything other than your camera moves (or changes), you should calculate final gather each frame instead of using a saved final gather map.
Hi Jeff,
Thanks for the reply re: converting your max mr materials for maya use. I think when I have some spare time I'll try and manually recreate your mia shaders in maya and see how viable/quick that is. I'll let you know if I make any progress.
The xml way sounds interesting but I have zero scripting skill so that's a non-starter for me.
