What is a rib file? A text file of grapics instructions that's what. See the rib file below. When "rendered" using Renderman, it produces a .tiff image like the sphere shown below.
Go and buy Essential RenderMan Fast by Ian Stevenson.
Don't just stare at this - Go and buy it!
While you're waiting - First you will need to install Renderman - well actually you don't- there's no such thing as RenderMan - well at least not as a standalone. Its "contained" in other packages. Considering only the free ones, 3Delight is the best - actually it's great . A minor problem is that you will have a great big 3Delight water- mark plastered over your lovely tif images. It is possible to get rid of it - but I'm not telling you how. : -)
Download 3Delight as follows:
On this page you will also see 3Delight User'sManual. Download this as well for instructions on how to set the path etc.
You may be surprised to hear that all of the installing and running of RenderMan is done from the command line.
In my case, after installation, I found that the environment variable %DELIGHT% was set to "C\Program Files\3Delight\.
My Path was set to "C\Program Files\3Delight\Bin"
(You can check your environment variables by typing set at the command prompt.)
My renderdl.exe was found installed in this "C\Program Files\3Delight\bin" folder.
In my case, I chose to work in the "C\Program Files\3Delight\bin" folder, so change to that folder if you wish to do the same.
Now we need to make the text file called test.rib. This can be done from NotePad but I preferred to make the text file in Visual Studion which of course has better editing features
In any case, make the following simplest rib file and save it as test.rib - also to the "C\Program Files\3Delight\bin" folder.
Display "test.tiff" "file" "rgba"
Translate 0 0 2
Sphere 1 -1 1 360
Leave out #test.rib if you wish, since it doesn't do a thing.
From the same folder, type renderdl test.rib. Ignore the message about the 'licensing.pdf' after the internet site is referenced.
All being well, a corresponding .tiff file will be produced. Take a look in the C\Program Files\3Delight\bin to make sure that test.tiff has been produced.
Now we need to view our .tiff file. If you take a look in the C\Program Files\3Delight\bin folder, you should also see the i-display.exe. Run this by typing i-display test.tiff at the command prompt.
Your complete (hence the 360) sphere of radius 1 (hence the 1 -1 1) should appear:
A word of explanation.
It ain't very clear in the aforementionted text (I dont know if the author expects
his book to be read by johny-come-latelys like me) that the x-axis is to the
right, the y-axis is up and the z-axis is into the screen. A left-handed system!
If you try increasing Translate 0 0 2 to Translate 0 0 3 and repeating the above
process, you should find that your sphere is disappearing into the screen.
(What happens with Translate 0 0 0 ?)
I found it very useful in the experimental process to place some 3-D coordinate axes on the tif image as well. This helps you get orientated. Try drawing a red thin cylinder along the x-axis to the right, green along the y-axis up and blue along the z into the screen (the usual colour convention for axes) and place small identically coloured cones at the tips. That can be your homework.
Take a look at to http://www.linuxfocus.org/English/July1999/article81.html to get the idea of these coloured axes but note the differences. His axes have been rotated so that z points up etc (still the same left-haded system). Also these ribs have actually been produced by RenderMan API functions which is another story which we will shortly discuss. This web site is truly excellent. Bookmark it - we shall return when we consider the RenderMan API.
Where to go from here? Read the first 15 chapters of the above mentioned RenderMan Fast.
Now that you know all about rib files - forget it - I am reliably informed
that no-one in the industry bothers.
Only kidding, it is very useful to have an understanding of rib before proceeding with CG, even though I'm told rib is a bit mundane for those Toy Story boys.