christosviskadourakis Posted January 11, 2016 Share Posted January 11, 2016 Hello there, I am trying to add some fog for the first time using Vray. I want to have some post-production, so I want to render my fog as an element and then add it in photoshop. I have tried to use VrayAtmosphere but no matter the intensity I tried (from 0,1 to some billions...) the element of VrayAtmosphere is always black. I have searched in Google and I have found that you can use the VrayEnvironmentFog Effect but instead of using it in the main image, you can use a black overdide material and this effect "on" and re-render your image. What you get you then use it in photoshop just like the VrayAtmosphere. The problem with this is that it takes the same amount of time in order to complete as the main render and that is killing me. So I would like to know if there is a way to use the VrayAtmosphere element because it is way faster. Thanks Christos Link to comment Share on other sites More sharing options...
Andres Saarnak Posted January 12, 2016 Share Posted January 12, 2016 I think VrayAtmosphere works only when using fog. With pure black material override it should render considerably faster. Last time I used fog, I rendered it out the same way separately with pretty low quality and then reduced atmospherePass noise in PS. That saved quite a bit of time. Depending on what you are trying to achieve maybe you can use zdepth for fog? Link to comment Share on other sites More sharing options...
Chris MacDonald Posted January 12, 2016 Share Posted January 12, 2016 The VRayenvironmentfog IS the atmosphere pass. Link to comment Share on other sites More sharing options...
christosviskadourakis Posted January 12, 2016 Author Share Posted January 12, 2016 What do you mean with your 1st phrase? I don't understand it. I kept settings the same to be honest. I will try your suggestion about noise in photoshop. Can you tell me what setting did you lower? I mean, you talk bout the settings (subdivs) of the VrayEnvironmentFog or the settings of Vray? I have already a Zdepth element to give blur to the back of my image, so using again the same element for a different task might not be a good idea. By the way. The render keeps going...this is redicilus, the main image took 4 hours to complete and the render for VrayEnvironmentFog (with blavk override material) keeps going for 11 hours and it needs one more hour approx...This is madness Link to comment Share on other sites More sharing options...
Chris MacDonald Posted January 12, 2016 Share Posted January 12, 2016 What he means is use an override material to set everything to black in your scene (hide any glass, as this will be back and block light), then render the image with lower GI settings (not fog subdivs). This will render much more quickly than running it on your final RGB pass, and give you the option to remove noise in photoshop and comp it as you want. Increasing the step size will also help speed things up, but you may begin to notice "steps" in your fog. On a normal architectural interior I'd go for a value of 500mm for this, but if you were rendering say... clouds that are kilometers long, then you could get away with a far, far larger value. Try reading the manual and looking at the examples: http://docs.chaosgroup.com/display/VRAY3MAX/Environment+Fog+%7C+VRayEnvironmentFog Link to comment Share on other sites More sharing options...
christosviskadourakis Posted January 12, 2016 Author Share Posted January 12, 2016 Thank you very much! I work on an exterior scene. I don't render clouds though but I want the feeling of mist. I kept the steps to default (this is 4cm if I am not wrong). Also, as long as I work on an exterior scene, I don't have to hide glasses or water surfaces, right? Link to comment Share on other sites More sharing options...
Chris MacDonald Posted January 12, 2016 Share Posted January 12, 2016 Yes, that's correct. On an exterior (depending on how large it is) you could probably get away with 1000mm or more for your steps setting. You could as Andres said use a ZDepth pass to simulate fog in the distance, but obviously this won't take into account any lights in your scene, so you wont get those volumetric "god rays" that people like to see. Link to comment Share on other sites More sharing options...
christosviskadourakis Posted January 12, 2016 Author Share Posted January 12, 2016 Ok but noone till now told me why the VrayAtmosphere element is always black Link to comment Share on other sites More sharing options...
Chris MacDonald Posted January 12, 2016 Share Posted January 12, 2016 It shouldn't be if you're using the environmentfog. Link to comment Share on other sites More sharing options...
christosviskadourakis Posted January 12, 2016 Author Share Posted January 12, 2016 It shouldn't be if you're using the environmentfog. EnvironmentFog looks lovely but it is an effect under the "8" key. The VrayAtmosphere is an element (like Zdepth or ExtraText). They are two different things. One looks nice and one looks black Link to comment Share on other sites More sharing options...
Chris MacDonald Posted January 12, 2016 Share Posted January 12, 2016 Yes, the atmosphere pass is so that you can have the environmentfog as a seperate pass for comping purposes. The reflection is in the vraymtl, yet there is a reflection pass element... That doesn't mean the two are different things. Link to comment Share on other sites More sharing options...
christosviskadourakis Posted January 12, 2016 Author Share Posted January 12, 2016 Yes, the atmosphere pass is so that you can have the environmentfog as a seperate pass for comping purposes. The reflection is in the vraymtl, yet there is a reflection pass element... That doesn't mean the two are different things. So you actually say that in order to make the vrayAtmosphere to work, you have to enable the VrayEnvironmentalFog? Link to comment Share on other sites More sharing options...
Chris MacDonald Posted January 12, 2016 Share Posted January 12, 2016 Yes. Or VRay Toon, which is also an atmospheric effect. Link to comment Share on other sites More sharing options...
christosviskadourakis Posted January 12, 2016 Author Share Posted January 12, 2016 Yes. Or VRay Toon, which is also an atmospheric effect. I would like to thank you very much! Have a good day Sir! Link to comment Share on other sites More sharing options...
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