View Full Version : Vray rendering question

12 December 2010, 08:41 AM
I have just started using Vray and I'm having a very wierd effect when I try to render my scene. The render comes out looking like a watercolor painting. Now I'm not sure if it's because I'm using vray materials with my textures attached to them or because I dont have some render settings right, but I'm kinda stumped as I dont really know vray all that well yet. Also, in the second render I'm getting some horrible overexposure around the bottom of the windows and benches, but if I move the area light I have there further back or lower the intensity it makes the right half of the image too dark. This interior rendering is a bitch.

12 December 2010, 09:31 AM
these blotches are due to your global illumination settings, my gues would be that you are using light cache as a secondery render engine,you need to get smaller samples and more of them into the scene so you will need to modify the scale of your samples, its a bit dependant on your scene scale, maybe a screenshot of your settings.

12 December 2010, 09:43 AM
as for the over exposure, it could be that you are using the vray sun sky model, when working with the physical sun sky one should also work with a physical camera, you can activate it by going to the camera atributes and looking for vray settings and then selecting physical camera, then you can play around with it as if it were a real camera, adjust the iso or f stop or shutter speed, wich ever on suits your needs.but be warned, you probably will spenda lot of time lighting your scene to get it right if you dont know what you are doing. also you might want to read up on vrays color mapping system.

12 December 2010, 03:13 PM
That watercolor effect you are getting is because of your GI settings. This looks like you are using Light Cache as your primary. Right now, You are using Nearest as your Filter type. If you will be using this method as your Primary, you should switch the filter type to Fixed. This will help remove that watercolor mosaic effect. Again, this method is not as accurate but it is a fast solver.

I would advise to not use Light Cache as a primary but it is better used as a Secondary bounce. In enclosed areas such as your scene, i would use Irradience Map for Primary, and Light Cache or Photon Map for Secondary. In an open area, i would use Irradience Map for Primary, and Brute force for Secondary. Now this can be different depending on your actual scene but i usually start with that rule when setting up scenes for renders.

As far as your exposure goes, VRay has a very powerful Color Mapping option. Under your render settings, go to the VRay tab and look for Color Mapping. It is right under Environment. Inside Color Mapping Type, it is probably set to the default of Linear Multiply. Change this to Exponential. Check to see if this reduces the burnt windows. If it is still giving you problems, switch it to HSV Exponential. It will remove white completely from the light and rely on colors. I find that you may get a more dull look but atleast its not burnt.

Please let me know if this helps or if you need further assistance!

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12 December 2010, 03:13 PM
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