Compositing

[Marshall_Craft]

Hi, I've read through as many threads as I could find (and understand) on this topic, and I have encountered some trouble implementing some of the strategies I've found. I'm using Vray 1.46.xx, VIZ 2006, and Photoshop C2. I know that PS is not considered a good program for compositing, but since we don't do a whole lot of walkthroughs (we're architects, so no character animation at all,) we don't have much of a need for AE or combustion or some other software I've only heard of. I used the Linear Color Mapping mode with the default values for Light and Dark multipliers and I unchecked "clamp output."

In PS, I used the Multiply mode for combining the Raw Direct and the Raw GI with Diffuse (separately), and then added the two results using Linear Dodge and also used Linear Dodge for adding everything else (Reflection, Refraction, Shadows, etc.)



RGB straight from VFB

Composit image done in PSC2

Can anyone guess why I lost my materials on the chairs and what are the general tools people have been using in PS or some other compositing software to improve the final product (exposure, contrast, color balance, etc.)? I'm very new to compositing and these more complicated settings of Vray, but I'm extremely interested in gaining more control over my renders (and in gaining the ability to add filters to certain parts of the final composition.)

Any and all help would be greatly appreciated. Thanks.

- Alex

[vlado]

What are the materials of the chairs?

Best regards,
Vlado

[panthon]

Well i guess you have lost your reflection channel. The missing materials could use some reflection and thus, the lack of this particular channel makes them look wrong. Try to compose reflections and refractions on top of the illumination information (gi).

[Marshall_Craft]

You're absolutely right; the reflection channel was missing, but you'll see the chair still isn't showing up correctly in the diffuse channel. The chair was just a merged element from VIZ's tutorials and uses a multi-subobject mat with standard mats. I'm trying to fix this by isolating the chair and rendering it using Vray mats hoping that does the trick.

Also, on the wall next to the closest chair, you'll see the bright spot from the RGB image is missing. Should that be on the Specular channel? And is it weird that my Raw Light channel is absolutely black???


Thanks guys.

- Alex

[RErender]

If your going to be layering , you really need to use all vray mats.

[gilpo]

I second RErender's suggestion. We had terribly inconsistent results when using standard materials while compositing.

[Marshall_Craft]

Yeah, I just proved your suggestions correct by changing out the standard mats with Vray mats. I know that most people here who composit do not use Photoshop, but do use unclamped HDRs. I read in another thread that PS automatically clamps the HDRs so I have just been using Targa files. Can anyone recommend a better way of compositing with PS? And why can't I output to "OpenEXR" as I've also read is a better solution? Sorry for the beginner questions, but I keep searching for clarification, but most forum users seem to either already know this stuff or just don't bother to ask. Thanks for the quick responses fellas.

- Alex

[panthon]

First at all, if you don´t use vray materials, it will render black in the vray channels. Secondly, in your situation, i would choose openEXR. Don´t forget to untick clamp output.

You must render with your output already set; if you try to save it from the framebuffer, it won´t work.

Let us know how it evolves!

[Marshall_Craft]

panthon,

I can't locate the file extension anywhere within VIZ's or Vray's Render menus. I have every G-Buffer channel selected and "clamp output" was unchecked. I feel like I must be overlooking something quite obvious. Again, thanks for baby-sitting me on this.






- Alex

[Daniele_ve]

You can write OpenEXR file with a free plugin you can download from

https://my.splutterfish.com/fish/fil...eased/OpenEXR/

[Marshall_Craft]

Thanks! I've been reading through every post I could find on HDRs/HDRI/and OpenEXR, and I found the plug-in for PS but couldn't find one for MAX/VIZ. So, thanks! Does anyone know of a book for dummies that would cover some of this stuff? I feel like the more I learn about rendering and compositing the less I really know. How do you guys learn all of this?


Again, thanks.

- Alex

[panthon]

Oops! I´m sorry. I thought u were using 3dsmax 8. In max 8, you find exr as an available exporting format without additional plugins...

You should test the options in exr just rendering different versions. I usually bring all the sliders and values to the maximum and it works fine...Some people may argue about file size, but in my case, i prefer to be safer instead of crunching the image size.

Anyway, i don´t use exr anymore. Our pipeline is based around rpf 32 bit, but, unfortunately, photoshop can´t open this format.

The answer to the learning question is simple: go ask here! . If you are lucky, u get answers from some elite guy floating around or in his coffee break

[Marshall_Craft]

Yeah, sorry, I may not have mentioned what version of VIZ (MAX) I'm running. Anyways, I now have the plug-in for MAX and for Photoshop, but the amount of functions and options available in the OpenEXR format is overwhelming. I feel like I need to learn more of the theory behind CGI and digital imagery in general to feel like I'll know what I'm doing. Anyways, I'll tinker with it.

Once I open the OpenEXR files in Photoshop, should I just composit them the way I have been doing (layer and group them and use Multiply and Linear Dodge blending modes?) I'm still not completely certain on how to utilize all this HDR stuff.

Thanks again Panthon.

- Alex

[Marshall_Craft]

(edited for redundancy)

[Dynedain]

This is an early test render for my currect health care project. I'm using all Vray Light Mtl on some tubes I'm using for fluourescent lights. This was done with low IR and LC settings. I guess I'll try to get the same effect using Vray Lights, but do you guys recommend distorting a sphere into a tube or just using a plane for this scene?

Please don't double post. For a new rendering with new conditions I'd recommend a new thread.