Lighting & MR Advice Exchange

#26

Two things come to mind on that bio.

  1. Exposure control could help control the amount.

Or

  1. Place an output map in the color slot of the light infinite shader. That will allow you to adjust the color & brightness of the light through the shader.
#27

:smiley: exposure control! that’s the thing that makes it work! Thanks folical!

I have another question for ya all:
I’m trying to use the glow shader (i took the neon from the CGTalk .mat file) but it doesnt seem to react much with the objects surrounding it? Am i missing something? Im just using FG!

#28

just jank up the brightness setting from 1 to 10 - 20… until the glow shows…

also check your units and system units to be real (don’t have a room that is 280 m, km, mm … high (keep it 280 cm or someting like that, this is because all the radius and energy settings from mental ray will be set in that scale, and if your units are bananas you will not have any control )

on the same topic :
glow only seems to work with fgather
i would love to have a glow that uses photons… that way you can control the bounces with the “photon map shader setup” folical has mentioned…

i did a test with only one glowing sphere in a room (only one extra omni turned on/off to kill the default lightning from max)
couldn’t get any glow around the corner, so there is no bounce.
have a look at my test renders attached

mabey a shader can be made to selfilluminate an object using photons?? (i did some wild tests but had not succes sofar…)
anyone has any idea about this?

#29

Just a thought, you can always fake object emitting photons by placing an omni light inside the object and using the photon shader to allow the photons to pass through like this:

Here’s the scene incase anyone wants to have a look (it’s animated, but I didn’t have time to render the animation).

Scene:
Download photon lights

#30

i have been doing some reading on lighting in max and have found a really usefull trick to create fake shadows…

As you all probably know, most of the computation in a render is processing shadows

To cut down rendering times you can fake shadows by setting a light to a -1 multiplier and turning off cast shadows… This can be used to darken corners of rooms etc…

ie if you were to place an omni light with the above settings in a well lit room in the corner … the corner will then become darker as if something is casting a shadow…

This can work well for photorealism but a good grasp of where shadows will be is needed…

hope someone finds this information usefull

kind regards

nebille

#31

for the direct light problem -

couldntyou merely create a spot a long way away but cut down on rendertime by using attenuation controls? then you should get the best of both worlds.

#32

Folical9, what do the splines do?? i couldn’t find anywere were they were used so i had to ask :slight_smile:

thnx

#33

Abbegon, the splines are paths the glowing spheres will follow in the animation. I have the omni’s linked to the spheres and the spheres follow the path. It just took too long to render on my PC but I have motion blur setup as well if you enable it in the render rollout.

#34

ah ok… :slight_smile: thnx

#35

Hello. New Max 6 user here. Thought I’d post my first attempts with GI and FG. Just a simple room with default materials. I was going for smooth lighting, no artifacts, and a fast render. This scene renders (on a P4 2.66GHz system) at 2 min 22 sec, with about another minute or less for photon generation and FG processing. Add a few more minutes if turning up AA sampling for a final render (which I didn’t do).

The scene contains 1 MR Area Omni (10x10 area sampling), with inverse-squared falloff.

As stated previously, exposure control is key to getting good lighting, as well as paying attention to scale. Mental Ray is pretty sweet. Definitely worth taking the time to learn and tweak for the best results. Here’s the scene if anyone’s interested:

GI/FG testing scene for Max 6

#36

As far as night time lighting with mr, i got great results with the lume night lens effect. This scene is set up with two standard (kind of dark purpleish) omni lights, one is set up as a the main light, the other is just to fill in the shadows a bit. The shadows are raytraced. All the trees and bushes are from the aec follige.

#37

47Gut: Could you post your scene? Or another simple scene like that?.

#38

another topic with MR. its only an idea from me. i dont like mentalray at all. i used some other third party renderers and when im comparing… . the main problem i see in MR is its speed. only an idea:shrug:.

#39

anyone have something about this subject?

as i see there are 3 lights:

  • standard
  • mental ray
  • photometric

i did a simple test and did not noticed any change between standard and mental ray lights. unfortunately, i still do not have a good place to post the images, altought there aint much thing.

all tree lights, with final gathering, took 5 minutes and a half. visually the difference is only between photometric and the other two, altought an “area shadow effect” i could only get with mental ray light with ray traced shadows. :shrug:

anyone have any experience with different light types with mental ray?

eks

#40

maby another problem. mentalray in some cases like this is limited :D. lighting in mentalray seems too weak to me.

#41

i strongly disagree with arona in one point, but agree in another.

i do think lighting and shadows makes mental ray stand out. but it definitly is slow.

so, any one have tips about mental ray optimization? to reduce it´s render time without too much loss of quality?

eks

#42

mental ray can be as fast as other solutions
only the room for error is a lot smaller…
once you know the ‘tricks’ it is possible to have acceptable rendertimes
there is no golden solution, just try untill you find your workflow that suits you
and look around and search in forums like this how other people do it…

and if you still don’t like… pls stop complaining and don’t use it :wink:

#43

Even though the direct lighting problem was posted a while ago, maybe other can benifit from this info.
First of let me clear the issue that the sun does NOT casts soft shadows. It cast hard defined shadows, that being because all the light rays from the sun are parallel, which is what a direct light is. If you have a pole and follow the shadow during the day it does apper to fall off or become lighter the further you get away from the pole. But the fall off is do to the light scattering in the sky and reflecting back down to the ground and lighting the surface. So to make the soft shadows in MR you would have to enable GI and or FG and then the shadows will look more realistic and have soft shadows like the picture Herbert West posted.

I am currently experimenting alot with mental ray to accuritly light a House that I am modeling and one of my biggest challenges is to get the interior lit correctly with only the daylight system. The interior is always to dark, not enough light is bounced. If anyone has any tips, please post them.

I think this is a very useful thread if as many people posted as in the Photon shading thread by Jeff Patton, and I hope to help as I figure out more settings and tweaks

#44

hay jeff i rendered that scene that you posted it work great but theres a small prob with the light in the courners of the room they seem the give off funny shadows like patches that move strange when the balls move around?

#45

You’ll have to increase the final gather and/or GI settings to get rid of those artifacts. Naturally, that will increase the render times too though.