Lighting accurcey

# 1 23-02-2005 , 03:04 PM

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Hi there all,
I have been working on modeling a full interior house, and pretty much got the basic sculpture done. Now I am working on the lighting part though I have one question.

When I first tried applying lights, in my book that comes with Maya 6 unlimitied, it describes that if you do not turn on depth map shadow light will pass through all abjects. So following the tutorial I placed the spot light inside the lamp and turned on depth map shadow. Though the problem that I got was that the body of the lamp didn't light up. Though after placing an additional point light in the center of the room and setting its instensity very low, it started to define the body of the lamp better and giving better results throughout the entire room.

Now in the past I thought I heard that Maya is pretty accrurate with lighting. Though my question is if this is true then why do I need at least 2 lights to properly light up a lamp and giving a room better definition?

I have posted an image of my 2 renders. The first showing lhow I used 2 lights to get a better results and the second being my first try with one light. BTW I appollogize for the 2 images being so small but I didn't want to place to seperate images which can lead to slow downloads here and knowing that the maxuim image size is 800x600 I didn't want to break any of the rules.

Though anyway as you can see, the image to left is still not the greatest but you can get the idea what I am pointing out that it is a lot better then image to right with only one spot light.

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# 2 23-02-2005 , 04:19 PM

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I'm not sure, but I think it might have something to do with light being reflected from various surfaces, such as walls ect., in real life, and not in Maya...

Liter is French for 'Gimme some ****ing cola before I break vous ****ing lips!"

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# 3 23-02-2005 , 11:12 PM

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So should I do it this way or...

Thanks blomkaal, but I have a question about your post.
So if it is because in real life that lights are being reflected from various surfaces, are you saying that I should use more than one light to get the effect I am looking for, or should I maybe use a blinn material and increase the reflection or even possibly turn on raytrace?

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# 4 24-02-2005 , 06:30 AM

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im am by know means a lighting or rendering expert. But i think you can't just have the spot light. The reason is, is that in reality there will almost always be some ambient lighting. Caused by light bouncing off sorrounding objects . Basicly each object becomes an additional source of light. To do this in maya, one way is to use mental ray and turn on global illumination for your light sources. Another way is too just use an ambient light to simulate this bounced light. Another tip someone gave me once, is too never have completely black shadows. Set the shadow to an almost black dark grey. Also you might want to soften the shadows slightly by increasing the light radius in the raytracing options fot the spot light.

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# 5 24-02-2005 , 05:11 PM

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I'm no lighting expert either, but I agree with Aidan... From what I've seen, I think the way it's done is to use additional light sources...

Liter is French for 'Gimme some ****ing cola before I break vous ****ing lips!"

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# 6 24-02-2005 , 06:55 PM

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Thanks to the both of you. Being a true newbie in lighting, I have been trying your method as to using mental ray. When I purchased Maya unlimited, it also came with a book which does include global illumination. However follow the tutorial in the book it describes that to get the best understandace of global illuminatiom, it is best to use comparisons of each render.

1. So doing so it first shows you to render without global illumination, and save that render. (see pic 1).

2. Then it tells you to turn on global illumination and save that image. (see pic 2)

3. Then the current render I am working on, is describing to change the photons intensity fromm 8000 to 120000. Though everything got washed out, and yet the picture in the book deosn't look like my picture. (see pic 3)

what am I doing wrong or is there a missprint considering that 120000 is a dramatic change?

pic 1

user added image

pic 2

pic 3

Last edited by junkyBob; 24-02-2005 at 06:57 PM.

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# 7 28-02-2005 , 12:24 PM

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not sure about the last one (are you reading it right 120000 is a huge difference from 8000 maybe it's a typo and should be 12000 that would make more sense!) user added image

As for the other part of the post. That's exactly right light doesn't bounce in cg you have to fake it. Turning on raytracing isn't always the best solution so yes you will need more bounce lights and fills than in real life to get the same result.

Alan

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Currently working on: Your Highness

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# 8 02-03-2005 , 02:03 PM

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Originally posted by Pure_Morning
...are you reading it right 120000 is a huge difference from 8000

Originally Posted by

Yep, I have double checked it and counted the zeros. I wonder how much of the rest is a typo considering that even though I came upon this, the rest of the tutorial either didn't come out right either. Is it possible that any of you who still have your "Getting Started with Maya Unlimited 6" book and check if it says the samething?

As for the other part of the post. That's exactly right light doesn't bounce in cg you have to fake it. Turning on raytracing isn't always the best solution so yes you will need more bounce lights and fills than in real life to get the same result.

Originally Posted by

... and thanks a bunch for the tip on lighting. You have cleared up my undtandance of lighting.

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