Render Elements

[robdeja]

I'm not sure exactly what's going on but render elements seem not to be working correctly

I made a test Cornell box scene and have lit it with a vray area light and used a standard Max camera( have also tried with a spot light). Basically where I would expect to have elements containing only shadows it comes out black.

I have also been looking at the Vray examples page for render elements and there is an example of direct lighting pass but no such element available in max ( am I required to make this my self from combining other passes?) proving tricky as there just coming out black.

There is no data for shadows etc in the Alpha as a side note.

Hopefully the image below will highlight the problem



I will add more to the post if it is not understandable or clear


Thanks for any help.

Also is anyone going to Mundos Digitales? Or Siggraph? this Year

[vlado]

What materials did you use?

Best regards,
Vlado

[vance3d]

Render elements won't work properly if you use anything but vray materials. that being said, I'm also having problems with Render Elements not working properly either. What I'm finding is that no matter what combination of elements I use I can never build the image and have it look like the full render.

If I could work backwards and subtract elements from the full render it seems that things like selfillumination, reflection, and refraction are correctly produced. What I find is that what is left, which if I understand correctly should just be vraylighting pass which is in itself a combination of diffusefilter, vrayrawlight, and vrayrawshadow, seems to have more light information in it than it should.

I have to continue testing this and maybe its a problem with some of my materials like vray blend, but I'm just not getting the results I need.

V Miller

[robdeja]

Thanks guys,

yes we figured out that we had some standard materials in the scene which was causing the problem! Panic over

[robdeja]

I'm also having problems with Render Elements not working properly either. What I'm finding is that no matter what combination of elements I use I can never build the image and have it look like the full render.

...

I have to continue testing this and maybe its a problem with some of my materials like vray blend, but I'm just not getting the results I need.

V Miller

Just to add, what I do for basic compositing in Photoshop using vray render elements is as follows;

- imagine this bunch of text is the photoshop layer palete (working from the bottom-up) -

VraySpecular-Lineardodge
Vrayselfillumination-linear dodge
Vrayreflection-lineardodge
VrayRefaraction-lineardodge
VrayGlobalillumination-lineardodge
Vrayrawlighting-Multiply
vraydiffuse filter- Normal

I then put z-depth as a new layer in channels and also vraymatteshadow as a new layer in channels to be used as selections for added control.

This gives me an image identical to that of a full render.

Hope this helps

[Infrared digital]

Hi Rob

I just rendered a scene over night and decided to try your compositing technique but, I couldn't get an exact rendition of the full render as below - the first one is the full render with the second being the composited render;







I trust that the zdepth and vraymatteshadow are for control and not essential for the compositing of the image ?

Also, where is vraymatteshadow - couldn't see it?

Incidentially, I'm not using LWF if that might be the problem.

thanks

N

[robdeja]

Try using VRaylighting and not VRayrawlighting....I'm not sure why you get slightly different results. I might have a play and get back to you on this.

And yes, the passes added to the colour channels are just for extra control.

[vlado]

You seem to have used some kind of color mapping. For compositing you always need to render in linear space. Otherwise, you will not be able to reconstruct the full render (that is, unless you can do some filter to first remove the color mapping and then re-apply it to the final result, which most compositing apps would have difficulty with).

Best regards,
Vlado

[Infrared digital]

So, I have to use LWF ?

[joconnell]

Any kind of maths based blending mode won't work correctly unless you're working in linear - the gamma curve on the elements will mean that you will get a slightly different amount of blending across the shadow, midtone and highlight.

[vance3d]

The idea of render elements pre dates anyone working in linear space and I don't recall it being a prerequisite of using render elements. The scanline renderer has had render elements for ages and its always worked no matter what format you rendered to.

V Miller

[vlado]

The idea of render elements pre dates anyone working in linear space and I don't recall it being a prerequisite of using render elements. The scanline renderer has had render elements for ages and its always worked no matter what format you rendered to.

Here, I mean simply linear color mapping, which both V-Ray and the scanline renderer do by default, so no problems there. I suppose it may be confusing with all the LWF threads around, but there the "linear" part describes what you see on the screen, not the renderer output (which, in that case, is not linear).

Best regards,
Vlado

[vance3d]

thanks Vlado,

I was replying to JoConnell. I read his comment as having to work in LWF to get render elements to work correctly. I apologize if this was an incorrect assumption.

Thanks,

V Miller