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vray render issue
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vray render issue // Archive: Tech Forum
Post by chrisj // Jul 11, 2007, 8:21am
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chrisj
Total Posts: 239
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Not sure if this has been mentioned already, but I'm a bit concerned that my renders look different with the new vray. Test renders shown below.
The brighter of the 2, and the poorer in my opinion is with the new software. As far as I can tell, the settings are identical. I don't want to have to re-texture everything, so can anyone give me pointers?
Cheers
Chris |
Post by trueSpaced // Jul 11, 2007, 8:29am
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trueSpaced
Total Posts: 544
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I actually like the lighter one better...
Sorry, I don't own VRay...
Just wanted to tell you my opinion...
-TrueSpaced:banana: |
Post by parva // Jul 11, 2007, 8:30am
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parva
Total Posts: 822
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can you share your mat settings? |
Post by chrisj // Jul 11, 2007, 8:36am
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chrisj
Total Posts: 239
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Here you go. Same file fro both renders, same HDRI settings with GI enabled, HDRI only. |
Post by parva // Jul 11, 2007, 9:23am
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parva
Total Posts: 822
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mmh, yes.... I know that there is a lighting increase in the new vray materials espacially glossiness shader produce a much brighter result. Don't know what's cause it.
Maybe you try to decrease the diffuse amount so that less color can be scattered and mainly reflection for the polish surface.
Btw. specular and shininess you don't need if you use the glossiness shader. It will have nearly no effects espacially if you use hdri. With reflection you control the shiniess and with glossiness you control the specularity.
edit: lol, I just tested my own advice and see that the diffuse amount has absolutly no effect with hdri. A setting of 0.01 should have a visible different to a setting of 1 but nope.... mmh really strange.
7441
Funny is also that the 1 diffuse version has no splotches but the 0.01 version hasn't.
The only thing which I see is to decrease the hdri lighting, mainly the back intensity. |
Post by chrisj // Jul 11, 2007, 11:10am
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chrisj
Total Posts: 239
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I'm finding that the ranges on many, if not all, of the material settings are different in 7.5. THe HDRI intensity needs to be reduced by a large factor, and there are similar issues with specular and shininess. Most inconvenient, as it means I may have to adjust all the textures of my 7.1 scene if I incorporate them into 7.5. I also find 7.5 vray slower. Not too happy about this. Alos, what is the 'exponent' materail parameter? Is it shininess?
I'm still testing, but it seems to relate to HDRI only. |
Post by chrisj // Jul 11, 2007, 11:12am
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chrisj
Total Posts: 239
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Definitely HRDI with vray. Lightworks seems to give the same result with 7.1 and 7.5. |
Post by prodigy // Jul 11, 2007, 11:14am
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prodigy
Total Posts: 3029
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Parva for me this is linked to my reported bug on difuse channel and GI.. |
Post by SiW // Jul 13, 2007, 8:35am
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SiW
Total Posts: 298
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The biggest change is related to reflections - V-Ray 1.0 treats all reflective surfaces as metal, where the reflections are affected by the color of the surface. The biggest problem there is that if you wanted to show a black reflective surface, you couldn't - no reflections would render.
This was addressed in V-Ray 1.5, with different behavior for different reflectance shaders - metal shaders still render like metal, but everything else renders like plastic, where the reflections are added to the base color instead of multiplied by it. As the glossy surface is intended for glossy plastic surfaces, that's what you're seeing. |
Post by Jack Edwards // Jul 13, 2007, 11:36am
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Jack Edwards
Total Posts: 4062
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Simon are you sure that mathematically it should be a 1:1 addition? Also can we get a metal version of the glossy shader then? LOL ;)
-Jack. |
Post by chrisj // Jul 16, 2007, 11:59am
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chrisj
Total Posts: 239
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problem I'm seeing is with the diffusion channel. no seeing any change when diffusion level is changed. |
Post by chrisj // Jul 17, 2007, 5:03am
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chrisj
Total Posts: 239
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Aaaargh!!
Is it just me having problems with vray 1.5 and GI?
All my existing scenes are ridiculously overbright when I load them in 7.5.
Even turning down the illumination doesn't help. The diffusion channel is redundant, as no matter the setting, the textures look the same. Beginning to regret upgrading now,as it's so frustrating that I cant achieve the results with 7.1 and vray1.
Can anyone make suggestions?
Chris |
Post by weaveribm // Jul 17, 2007, 5:28am
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weaveribm
Total Posts: 592
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existing scenes are ridiculously overbright
It's not just you Chris that over-bright lighting, it was exactly the same for me the lighting values will need to change but you will be able to achieve the same nice lighting after biting the bullet and setting up lighting again. It is frustrating I agree. The best tip I read in here is that the first GI bounce parameter governs the brightness of the scene. Drop the first and second bounce values right down to 0.2 or something and work your way up
Also lights and glass can lose their Cast Shadows etc values from Render Options best keep an eye on them
Peter |
Post by Jack Edwards // Jul 17, 2007, 5:30am
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Jack Edwards
Total Posts: 4062
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Hi Chris,
have you tried using the metal shaders instead of plastic (phong) ones? From what Simon has been saying the old version of VRay treated all materials as metal.
Can you also post a screen of a problem and grab of your material and GI or HDRI settings?
If you're using HDRI, I've found the default settings are way to strong.
Apparently there are major changes (done by Chaos Group) to the VRay core between the two versions, so it's not unexpected that the material and light settings would need to be changed.
Prodigy is having the same problem you are and I've noticed it with some materials and settings as well, it may be that something is working correctly now, where as before it was broken. What you're mentioning about the diffuse slider not having any effect seems odd though... :(
-Jack. |
Post by chrisj // Jul 17, 2007, 11:42am
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chrisj
Total Posts: 239
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Thanks for the replies. If you look back to my first posts, you'll see some parameters. I aslo think the settings for the 1st and second bounce have been swapped over. When you reduce the diffusion channel setting, you see the material appear darher in the material editor, but this is not translated to the scene when rendered. Look like a long night ahead trying to find a solution.
Cheers |
Post by Jack Edwards // Jul 17, 2007, 6:09pm
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Jack Edwards
Total Posts: 4062
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Doh, forgot about the first page. :o
I think Simon must've missed that changing the diffuse values is not working though...
-Jack. |
Post by chrisj // Jul 18, 2007, 12:19am
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chrisj
Total Posts: 239
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OK folks, after a bit of experimentation and comparison, I have now discovered 2 bugs, one in 7.1 , the other in 7.5.
The problem lies with area lights. I tend to use area lights to simulate window light, as for my study scene (see elsewhere in wip). I have now discovered that the falloff does not work in 7.1 at all. I normally use linear falloff for area sources, and set up intensity to suit. Images are identical for no-falloff, linear, and quadratic.
When I switch the same scene and settings to 7.5, with linear falloff, I find that the scene is completely washed out with light, and takes an age to render. If I set the area light to no-falloff, the scene renders almost identically to 7.1.
So, in conclusion, falloff for area lights does not work in 7.1.
In 7.5, the falloff actually increases the total amount of light exponentially, rather than reduce its effect.
Spot lights and omni lights appear to be OK (but I'll let you know). |
Post by roman // Jul 18, 2007, 9:44pm
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roman
Total Posts: 320
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In 7.5, the falloff actually increases the total amount of light exponentially, rather than reduce its effect.I believe this is fixed in V-Ray1.52. |
Post by chrisj // Jul 20, 2007, 12:11am
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chrisj
Total Posts: 239
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Good news Roman.
Thanks for your response.
Chris |
Post by prodigy // Jul 20, 2007, 6:29am
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prodigy
Total Posts: 3029
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chisj, yes in 7.11 (Vr 1.0) arealight doesn't support falloff, (i remember those days :rolleyes:)
But yes, good news are in comming... :) |
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