View Full Version : extended rpf

09 September 2002, 08:24 AM
Does anyone know what each item in the extended rpf is good for and which buffers are useful?

i know compositing can use most of them
the one thats i'm not too sure about are
real pix buffer
velocity buffer
coverage buffer

normal buffer (i assume is the normals of the object)
material buffer is surfaces i think.
objectid, fusion uses.

some of these i think only shake can use.


I've used most of the buffers successfully, but some of them, i'm not sure about the technical aspects of where they stem from.

09 September 2002, 01:04 PM
I think I can help....let me get to work and see what I can get together for you....

09 September 2002, 01:32 PM
Extended RPF Export
This filter saves images in the Rich Pixel Format, a popular SGI format that supports the ability to include
arbitrary image channels. This is the replacement for the Extended RLA format, popular for 2D/3D compositing work.

To access the Extended RPF Export filter, bring up the Image Processing window (^F8), click
“Add Image Filter”, and select “RPF Export: RichPixelFormatPic” from the pop-up menu.

To access the Extended RPF Export options, double click on it in the filter list. This will bring up the RPF Export window.

Give your file a base name by entering a name in the field or use the Image Base Name file requester
button. You can also use the file requester button to determine the location LightWave will render to.

The Extended RPF Export filter includes optional buffers:

The distance from the camera to the nearest object visible in a pixel.
Also known as the z-buffer.

Object ID Buffer:
This buffer contains a unique value for each object in the scene, and can be used to select
or mask an entire object.

Transparency Buffer:
This buffer contains the transparency value of the frontmost surface visible at that pixel.

Color Buffer:
This buffer contains the raw, unshaded surface colors.

RealPix Buffer:
This buffer contains potential high dynamic-range pixel data, larger then the typical 0-
255 range.

TextureUV Buffer:
This buffer contains the UV coordinates, if any, of the texture at that pixel.

Material Buffer:
This buffer contains a unique value for the surface ‘material’ at each pixel.

Shadow Buffer:
Indicates where shadows are falling in the final image. It may also be
thought of as an illumination map, showing what parts of the image are
visible to the lights in the scene.

Velocity Buffer:
This buffer contains the velocity, in screen space, of the surface seen at that pixel.

Normal Buffer:
This buffer contains the surface normal at a given pixel.

Coverage Buffer:
This buffer contains the amount of the object rendered at a given (abitaliased) pixel.

>>RLA24 is standard, old-fashioned, pre-discreet hack,wavefront format, in 24-bits.
>>RLA32 is the same thing, but with alpha (i.e.32-bits).
>>Deluxe RLA offers extra RLA hack channels like depth, etc. and also allows 16-bits per
channel (48- or 64-bit RGB or RGBA images). It must be used in conjunction with the DeluxeRLA
image filter, in order to get access to those extra buffers.
>>Another alternative for added buffers is the ExtendedRLA image filter, which saves images
directly from the filter, rather than using the saver. It does not have 16-bit per channel color
>>The replacement for the extended RLA format is the RPF format (Rich Pixel Format).

09 September 2002, 02:06 PM
thank you
thats very helpful!!

09 September 2002, 02:12 PM
I'll get a PDF version up today

09 September 2002, 02:17 PM
RPF Document

there you go!

09 September 2002, 07:04 PM
very cool!!!

I always wondered what some buffers did, and this just explained it very well!!

thx a lot!!

Michael JL
09 September 2002, 11:28 PM
I have to say Proton, you are an awesome addition to the Newtek team. I've seen more tutorials etc come out of newtek in the last month, than previously in the last year, seams to me anyways.

Keep it up !

09 September 2002, 12:00 AM
isn't that about the same thing as the psd saver in 7.5 ?

hey, there should be a tut on how to use that PSD in photoshop (set mixing modes etc.) - read that some time ago on flay but forgot to save.....

lets see.....

from flay :

A lot of people attending the LightWave Worldwide Training Tour have been asking about the Photoshop PSD saver in LightWave 7.5. Essentially, it saves out the buffers as discrete layers - but people aren't getting the results they want. Here's one way to use it...

Create an image with some reflections and specular highlights, and in the Image Filters section, apply the PSD Export Filter. Here's one way to use it - in the requester, click on the following buffers - Raw Color, Diffuse Shade, Specular Shade, Refl. Color. Click on Image Base Name, pick a location and give a file name. Do an F9 render - this will automatically save a .PSD. (Note that you don't need to have any save options selected in Render Options.)

Now, go to Photoshop, load the .PSD - the image looks like horrible death. No problem - we just need to adjust things. Look at the layers. The bottom layer is the full render. Above that is a black layer. Now, drag the layers in Photoshop so the layer above the black one is Diffuse Shading. Make the layer above that Raw Color AND (important!) change the blend mode of the Raw Color layer to Multiply. Better, eh? (All other layers should be Screen)Put Spec. Shading and Refl. Color above those and you have a close approximation of the final image - and you can tweak buffers with Photoshop's layer opacity controls. Have fun!
Submitted by Lee Stranahan

usefull stuff huh?

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