Rendering a bit strange on a white surface
In the image below, the bed is covered by a white sheet, defined by a mate material.
I think a bit strange it's rendered so grey.
Sides, directly enlightened by the lamps are white, I agree that the sides facing the camera are grey because in shadow, but I'm a bit surprised about the top of the bed.
Any idea?
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Replies to This Discussion
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Permalink Reply by Render Plus on
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In the rendering window, after rendering, left-click on the bed and select Edit material.
Make sure the material has the name you expect.
Is the color of the material white?
Does it have highlight intensity, a texture, or other properties.
If you placed the sheet directly on the bed in SketchUp - at exactly the same place - then SketchUp may be rendering the sheet while IRender nXt is rendering the bed. (If two surfaces are in exactly the same place then it is ambiguous as to which one is selected for rendering. This is knows an Z-fighting)
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Permalink Reply by Alain Bonnefoy on
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What do you mean by material name? except for maybe "Auto-Reflection" feature we recently talked about, is there any meaning for iRender?
I suppose the color was color_000 but not sure.
I tried with another color (color_E05) to see if white is particular but I got the same problem.
Intensity is 0, sharpness is 1, nothing as texture.
In fact, at the begining, the result is almost ok (3 passes here), as you can see i the image below. It gets darker later.
It's like if iRender wanted to show the difference between side mattress, illuminated by close lamps, and the top of mattress, illuminated by far ceilling lamp.
In fact, if you look at the bedside lamp position, they certainly enlight the top of the mattress as well.
I'm going to test with "white" color.
I also suppose I could get a good result if I remvoe bedside lamps. I'm going to see.
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When you left click on a material in the rendering window it will display the name of the material (here 96,96,96) and let you edit it directly while rendering.
When you click Edit Material, it will load the material into a wizard.
You can use this "trick" to make sure what material is actually being rendered, and whether the settings on the material are what you expect.
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I would also shine a light directly onto the bed to see if it turns white. It can be difficult to get white things to be absolutely white unless they have enough light on them.
For instance, the white wall in the images above are not white except where fully illuminated by the spot lights.
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According to your screenshot you have a grey wall no?
In that case, the result seems to be ok.
In my case I have a white surface, certainly enlightened by bedside lamps which are higher than the mattress, and at least enlightened by the ceiling lamps. I agree that a white object in shadow looks dark, but in that case, I think it looks too dark.
Maybe, the surface, as it appears to iRender is too smooth and does not reflect rays in the camera direction. Which could be the case of a white plastic surface but cannot be the case of a mattress in real life of course. If it's the reason why I get a dark surface, I can understand.
So, I could solve the problem setting maybe a sandpaper texture.
I'm going to check that.
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Here I placed the almost white "snow" material on the wall, and shone a bright spot light at it.
It renders white behind the spot light, but more gray in other places.
Since you can never get whiter than "white" on your monitor, things which aren't as brightly illuminated as the center of the spot light have to be less "white"
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I'm afraid that sandpaper texture won't help me much.
I'm going to explore indirect lightning. It's actually set to standard with only 1 bounce.
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Some lights near the ceiling would have a big effect as well.
And, finally, if you need to you can increase the brightness of the bed using Self Glow.
Here I added 10% self glow to the front face of the wall.
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ah ok, I'm waiting for the result of indirect lightning (very slow) and I'll look at this point.
But I'm afraid that self glow give strange result on other close objects, I'll see.
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2 hours to process only 2 passes with 3 bounces .....
Well, I think I'm going to try something else.
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Well, slef glow mattress cause bad result as you can see below.
I'm afraid I won't be able to find the right solution.
I wonder if it wouldn't be usefull to have a special attribute to define a surface able to reflect rays in all directions. If it's the reason why the top of the mattress looks so dark.
My point of view is iRender could consider the camera "blinded" by bedside lamps in first plan and if, for the engine, the mattress is a very smooth surface, it doesn't reflect rays back to the camera because lamps are "in front" of it.
what's you opinion?
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