#Height Field IPAS?
9 messages in this thread
Does anyone know of an IPAS routine that will produce an effect similar to the
height field object in POV Ray? I would like to model some fractal landscapes
but the conversion to a polygon mesh generates HUGE dxf files and less detail.
Is there a better way to do this?
–Nat'n
Nat'n:
What is the height field object in POV Ray? If you can describe the effect,
we'll see what we can to to achieve it!
Greg Pyros [Pyros Partnership, Inc] gpyros@pyros.com 29-Dec-93 at 8:56p PST
From the POV Ray manual:
"A height field is essentially a 1 unit wide by 1 unit long box with a
mountainous surface on top. The height of the mountian at each point is taken
from the color number (palette index) of the pixels in a graphic image file."
This is great for making fractals (or other images like the PCX files produced
in Vista Pro) into 3D landscapes! I have tried to do similar things in 3DS but
havent' come close to the detail possible in POV Ray. I tried to convert a GIF
to a DXF but this resulted in HUGE file w/o enough detail. POV ray actually
computes 2 small triangles for each pixel in the bitmap.
I would think that you could use an AXP or PXP type process to duplicate this
effect. You would need a parameter for the bitmap and could scale the
dimensions to the stand-in box. The POV height field can accept 8bit GIF
files, 16bit POT files created in fractint, and even TGA files for 24 bits of
depth information.
It sounds like the Yosters are working on something very similar!
–Nat'n
Nathan – Another approach which I really like is the one Digital Arts created.
You build a 2-D mesh for whatever level of detail you think you'll need and
then apply a B/W or Color image to it, (its based on grayscale contrast) and
depending on the values you set, the vertices are deformed. Its very efficient
in that it does not contstruct monsterous meshes (you define the size of the
mesh), and the vertices are pulled almost like a spline in continuity. This
means for instance you can create a large rough shaped cirlce or outline like
on a contour map of lets say 40% white and a second inner circle on the inside
(no gradient needed) with say 60% white and a third inner circle of 80% white
and you've got a smooth shaped mountain. If your image does have a gradient it
will follow it as closely as the detail of your mesh allows. Of course if you
set the parameters extreme and you don't have enough vertices you can get sharp
peaks, but if this happens you just subdivide the mesh a little more, reapply
the map and you're good to go. Typically this is not a problem and the smooth
shaders take care of the rest. FWIW
-JE
We're working on an IPAS3 PXP that will do displacement modeling by applying
the greyscale of an image to an object and deforming the object according to
the image. It will then do adaptive data reduction to greatly simplify the
resulting object, actually making it usable.
– G
>> We're working on an IPAS3 PXP that will do displacement modeling…
Excellent Gary! I was wondering when we would see this IPAS since I read
thru the docs on an SGI. I remember thinking what a great way to model.
Seems it took a while for this IPAS to really catch on but lately I think
I'm in IPAS heaven! Can't wait for IPAS3 stuff to appear.
-Ralph
This is just one of a bunch of very useful routines. Some of them are so
graphical that you'd never believe it wasn't part of the core 3DS code.
– G
Great!!
Any ideas when this might be available?
–Nat'n
We're currently scheduled to ship our new IPAS routines in late March or early
April.
– G