No idea how to fix it

[felipesosadiaz]

hi, i have a really strange problem.

When i render my scene normally renders good, but sometimes some frames are rendered just like in the pic i attached. As you can see in there the light calculations are ok but when it starts to actually render those bright colors appear. Anyone knows how i can i fix this? the thing is that this problem appears only in some frames. im using a vray sun, a half sphere with vray light material for GI and a vray camera. i attach my settings also.

 

I have read the problem is the color mapping. Thats the way of vray telling me that is too bright. So i clicked on the option of clamp output- clamp level: 1.

It helped a little bit but some frames are still not working.

 

any help apreciated!

[Scott Schroeder]

Check all of your materials and lights and make sure they are all Vray. The thing with incompatible objects is that they may render fine one frame and blow up the next.

[Ricardo Eloy]

Adding to Scott's tip, the way you can make sure everything is V-Ray is by right-clicking on the scene and using the V-Ray Scene Converter. ;-)

[RyderSK]

It's the leaf material, by 99perc. it's problem with translucency value (as per sss, not the vray2sided).

 

Also this : "a half sphere with vray light material" this really isn't smart way of illuminating a scene, not sure why you set it up

Edited December 1, 2012 by RyderSK

[Umesh Raut]

To me it looks more like clamped colors that appear as bright fluorescent spots. You may check the bottom row in VFB (view clamped colors button) to ascertain this; and then play with your (i) lighting, (ii)exposure or (iii) materials in that order. You may try adjusting the exposure before lighting as well.

 

@juraj,

the half (hemi)sphere with vray light is ok so far as you want to get good GI into your images. And he's also using vray sun (probably without vray sky....??)

[Nic H]

vray light material is a terrible way to light your scene

[Umesh Raut]

May be, but so long as you get good results with it why not use it. Nobody cares WHAT you've used; all they are interested in is HOW good it looks ultimately.

[Nic H]

ok it looks great congratulations

[felipesosadiaz]

Hi, thank you for all your input!

 

All my materials/lighting are Vray. The leaf materials are vray and with no tranparency.

regarding the clambed part Umesh Raut ... i didnt understand you very well. can you explain more pls?

 

And regarding the half sphere. I just find it a easy way to get some GI in the scene. But i guess i need to try a different way. any recommendations?

[Francisco Penaloza]

To me also look like a material issue, check the tree materials, maybe reset them, the VRay scene converter do not always work with some Mental Ray materials, so take a double look on that.

If you want soft lighting, you should check the Dome light with HDRI plus VRay Sun set up of Mr Guthrie

Last but not least, check your scale, there is a big difference between Cars, curves, bench scales in your scene; no to talk about that speed bump, very effective as it is

[felipesosadiaz]

thanks a lot francisco.. ill keep it in mind

[abhaysingh]

Material is the problem.Vray must be giving you overbright errors.It could be because of vray light material or because of rgb level of a bitmap set to high value.It could be other issue in material.

Sometimes overbright HDRI gives you bright spots but those are always white in color.

If you havn't found out yet then the best way is to divide your scene.You can divide your scene by similar objects(use Ctr+Q to select similar objects).

 

--Go to the frame(whichever has this problem)

--Hide half of your scene and press render, if it renders fine then render the other half.

--if both divided scenes have problem then look for similar objects.

--if one of the divided scene has problem then divide it further till you nail the culprit.

--Just to make sure it is not a light problem then render your scene in "Override material"(global switches).Assign light grey material to override mat.Hide your env. dome(vray light mat.) while you do this.

--look for all objects with vray light materials or the objects which have high probability of overbright mat. like flowers, leaves, signboards,billboards, street lamps etc.Hide them and render.

 

If problem persists then you can upload your scene with basic mesh and material+light and give it to me.I'll do it for you.

 

Hope it helps.Let us know.

 

About the vray light material dome (environment), actually lot of people follow it and surprisingly neoscape used it & they made a tutorial of their loft project showing thier production process.But i never liked this idea.One reason is you're prone to such overbright light leaks and other dark artifacts.It needs high GI settings.I mean it is good for neon lights or cove lights in interiors but not as the primary source of light.It doesnt give you smooth fall off like vray light plane or other light gives.Just test and compare light falling on ground plane from vray light mat and vray light plane.Even in low setting you'll get good results with vray light plane.It is just my point of view,but everyone has their own style of lighting...

 

Have a good day !

 

Abhay.

Edited December 4, 2012 by abhaysingh

[Umesh Raut]

Dear Felipe,

First of all, Francisco above has pointed rightly to the scale part, you need to look into that as well.

 

Now the main issue - its always good to have a vray sun+sky system as a starting point in your exterior scene with proper exposure set in the

(i) vray camera settings or

(if you are not using vray physical camera then)

(ii) max's own environment settings (key 8 on main part of the keyboard).

 

From there you start fine tuning the exposure with real world camera analogies applied to the scene vray camera or 8>Env. exposure settings. Then in vray frame buffer, there's a button to view clamped colors, which I thought is your problem in this case and I still feel checking and adjusting exposure in VFB itself would give you clean result. If you don't know these steps yet or are unaware of the exposure setting adjustments, then you need to learn a few things about real world cameras and their implied relation/similarities to vray physical camera.

 

Finally the light hemisphere. It could be termed as an alternative to the plain blue to light grey gradient vray places as sky env. map. You place a vray dome light and assign it a texture of an HDR image to light your scene in stead of the normal sun and/or sky model. That texture, when instanced to the material editor, can be controlled with its intensity and rotation for desired effects in scene lighting. Hope this should suffice.

 

p.s. the link to Peter Guthrie's tut above is a great source for such stuff, just in case.

[felipesosadiaz]

thanks to everyone!

so i finally solved the problem.

 

I was not sure what was the problem so i did everything you said at the same time an di t worked. I coverted all materials (eventho i think they were all vray alrdy) with the vray converted, i replaced the half sphere with a hdri system with Peter Guthrie tutorial, I clamped colors and raise up the settings a little bit. Also fixed the scale. Thanks to everyone, as soon as i finish the clip im doing ill post it here.

 

best regards,

felipe