Afterburn and V-Ray

Ive recently started work with an oil drilling company and Im 80% the way there convincing them to make the switch from Mentalray to V-Ray and they want to know how well Afterburn will work with V-Ray as there will be a call for it for some fire and smoke effects and possibly blowing up the odd scene :wink:

Any input or examples would be appreciated, If you dont want to post samples publicly please PM me and we’ll exchange emails..

Thanks in advance,

-dave

Works fine i’d say…we’re using both aburn and dreamscape with vray…there’s some additional stuff to take care of to keep rendertimes low but that’s about it. Aburn does have some strange oddities (like the rotation flipping etc) but those are known and not vray related

Thorsten

what do you mean by rotating flipping?

there’s cases were network rendering causes odd rotation issues were particle rotation seems to flip between two states…hard to explain..

Thorsten

>Does it happen when using particle flow? If so, you could use a cache operator in the PF stack.

we happened to have it with all kinds of particle systems…cache operator didnt help either. It’s only a network render issue tho…works fine locally.

Thorsten

yeah for some reason one machine will render differently to the others - it’s usually down to the regional settings of the computer being set to “,” instead of “.” which affects the random noise generator in afterburn - annoying stuff like that. I’ve found it often renders quicker in the scanline too as a seperate pass to be comped back over in afx. Sometimes vrays aa is overkill for an afterburn effect.

true, but that was mostly a no-no for us, because we had for example cars that had to properly intersect the smoke. that wouldnt be too much of a problem, but the mo-blur is a lot different in vray hence the smoke wouldnt match the beauty pass

Thorsten

When geometry is not intersecting the AB volumes, VRay is way faster. You can way undersample in VRay (or any image sampling renderer that supports AB). Here is a test I did with one of the files that comes with AB and I have done several small projects doing this. However, you need higher sampling if geometry is present. In a perfect world, you could specify AA sampling per entity type or perhaps even per object.

www.charleycarlat.com/Tests/AB_Scanline-vs-VRay.jpg
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btw the difference in the background sky have to do with using a different Rendering Type in AB.

There is a fix for flipping mapping

I was having that problem with afterburn and they sent me a patch that fixed the problem. This is about 8 months - they said at the time that they where going to release the patch with the next upgrade. I am surprized they haven’t released it yet.

I will look through my files and see if I still have the patch - if I remember correctly there was a thread on the afterburn forum and the discreet forum.

I’ve used afterburn and dreamscape (to a lesser extent) with Vray without any problems related to Vray.

there was a problem i sound ig you had a ground plane and wanted AB to cast a shadow on it then split the render into layers. the AB atmospheric effect is present in all passes when it really should only be present in the atmospheric pass.

I would not recomend rendering afterburn with vray. You can still use vray, and afterburn, but I would suggest to render ab in a spearate pass via scanline. Some reasons for that, shadows/shading will work better in scanline. You wont get speed improvements in another renderers since ab has its own renderer. AB wont show in your reflections in vray. And finally its not motion blurrable, not by vray anyways. That applies to any external renderer. Oneway to blur ab is through camera multipass, the other is with velosity vector which ab outputs.

I hate to disagree with you on this, but it is not my experience that this is so, with the exception of the MBlur.


32 Sec-Scanline renderer with Raytraced material and ABShadow light


17 Sec-VRay Image Sample @ -3 0 VRay Shadow light, VRay material with reflection.

Both VRay and Brazil (and I am sure MR if it was supported) out render the scanline with volumetrics by a good deal. As I mentioned earlier, the biggest downfall is when you need to have both geometry and AB together. However in somce cases it may be a slight bit faster to create a seperate mask with a higher Sampling and the geometry, but without all the shading detail of the AB. This allows you to render your AB pass free of geometry and use the mask to comp it together. I have done this in the past with good results. I do not however have any experience with using VRays split G-Buffer images, so I can’t comment on that.

right, i see. well perhaps thigns have changed since I used it last. :smile:

can you try to seperate your AB into passes? maybe im doing something wrong. i want a pass where the AB shadow is on the ground but the AB isnt shown. then another where the AB volumetric is shown (environment pass) the environent pass works however i cant get the shadow pass to work

I am not sure how to make the shadow split work correctly in VRay to begin with, much less with AB, so I would still do it the old school way.

Make everything else white except the shadow. As the VRay Shadow automatically self shadows the atmospherics, an easy way to not have to mess too much with you AB/lights setup is to use the Explode Deamon with a color of white, a high multiplier (10 or more) and use the Replace Color Blending mode. Set your ground objects to have Matte properties within VRay Properties and you are good to go. Also, don;t forget to set your background to white. This will give you your AB shadow agianst a white background for you to do as you wish within the comp.

If anyone does know how to get the shadow pass to work well with VRay, I would be all ears :smile:

Edit: It might be worth noting that playing around with the color of your AB volumes and the lights can get you some great power within the compositor, you can use different colors to create images for selections to isolate different qualities of the volumetric effect.

no, your not getting it. i know how to do a shadow pass. the problem im geting is that i dont want the stupid cloud in the shot with the shadow pass. normally if i want an item to cast a shadow on the ground but that we dont see the item i would turn off “visable to camera” however you cant do that with AB. Aura used to do this perfectly. when you rendered g-buffer elements Aura would show up on the environment pass yet it would not show up on any of the other passes like GI, Shadow, etc

I do not believe I am following you. You mean you want to see the entire shadow, even what would normally be occluded by the object or in this case the AB effect?

exactly. in the case of something i recently did i had a tower and a particle system going around it like a snake. the particles were set to size0 and used for the AB atmospheric effect. i wanted to have the tower on one layer with all of its passes (diffuse etc) and one pass i wanted was the shadow of the snaking smoke on the tower (without the actual smoke in the shot) then i wanted the smoke on another layer so i could have fun with the smokes color in post.

This can be done. Set up a scene as if you were going to do a shadow pass (white background, matte objects…).
-Set the AB density to .01
-in the Shadow Parameters of the Light, set the density to a value that gives the desired shadow amount (200 or so seems pretty close to the standard density).

This should give you a shadow only, the AB volumes will not be visable (or at least not enough to matter)