CADCAM,raytrace queries
7 messages in this thread
To ALL:
I dabble a bit in sculpture (mostly wax and clay) and am interested in
using the Amiga to help with some of the enlarging/construction plans. I
don't know much about the various CAD/CAM programs for the Amiga, or
ray-tracing programs, or even which type of program would address my needs.
Here's the problem I wish to solve, and any comments would be welcome:
How can I create a form in the computer and render it so I can look at it
from all angles–from above, below, any side, and any combination thereof?
Once that is done I would like to be able to slice it up electronically
into horizontal slices which can then be used as a template to form an
armature out of stryofoam or plywood or whatever. Imagine that I have a
computer model of, say, the statue of Liberty. Is there a program which
would allow me to "slice" it successively from the bottom up and give me a
printout of the perimeters at various heights?
I understand that the Renaissance sculptors used a method called "pointing"
in which a frame was built around a model or maquette, and careful
measurements were taken at various points by sticking a stick through the
frame and measuring the distance in to the model; many of these points
were taken and then laboriously transferred to a larger frame, and the
process repeated in reverse. That sounds like a simple job for a computer,
especially if the maquette, or preliminary model, exists in the computer's
memory to begin with.
What type of program do I need? CAD/CAM ? Ray-tracing ? I don't think I
would need animation per se, except that it might be nice to move parts of
the model around to explore how different constructions might work
aaesthetically.
Does such a program exist for the Amiga? How about on other formats? My
own setup is a stock A2000 with a GVP hard drive (105 megs). I have one
meg of chip ram and 2 more megs of ram on the GVP card. I was thinking
about getting an accellerator board sometime soon; if so, I would wait to
expand my ram, if needed, with chips the accelerator board could use.
Again, any and all comments are welcome, including "yer a crackpot–Rodin
Lee, I would say what you need is a good 3D Modeling program (3D CAD) to
slice a model and then output the different cross-sections. Most of the 3D
modeleling programs are also ray tracers but I don't think you need that
aspect of the program for what you are trying to do. Do you know the
difference between the two aspects? Some of the more popular such programs
are Imagine (best features but takes a while to learn), Sculpt 4D (not as
many features but a good modeling program) and Real 3D (best combination of
features and ease of use). I hear Draw 4D Pro is pretty good as well. The
only problem with all of the above is that you have to create the model
from scratch yourself. There is an abundance of ready made models
(objects) available here on CIS and many other BBS's. Most of them are in
Imagine format (did I tell you the objects are not interchangeable between
formats) but there are programs (Interchange for one) that can translate
objects between formats. Good luck and feel free to ask more questions.
Impulse (Imagine publisher) has a section in AmigaVendor forum. Later.
John
Thanks John, I'll check out those programs. Sounds like Imagine has the
most support out there.———-Lee
Lee,
Imagine's Forms Editor lets you create objects by defining a series of
key cross-slices and having the program interpolate them to the desired
precision. Like (almost) all 3-D programs, it has a Front, Top and Side
window, plus a Perspective window which will display the object from any
angle. If your object was constructed as a series of horizontal slices,
running from top to bottom, you could zoom in the Top window to full-screen
and use any PD screen-capture program to create a series of IFF images,
which could then be printed. This basically sounds like what you want to
do.
i A CAD program is a geometrically-oriented drafting program. Its
strengths lie in the absolute precision with which you can size and place
your elements. All good CAD programs let you define up to 255 layers, which
can be viewed or printed separately or in any combination. Many CAD
programs work in three dimensions.
Ray-tracing is simply a method used by the computer to render a view of
a 3-D scene. In ray-tracing, the computer casts a series of light rays that
start at the observer's "eye" position, pierce the computer screen at each
pixel, and then are let free to bounce off and penetrate objects in the
scene beyond the screen. This allows the computer to fully represent
shadows, illumination, reflections and refraction. It also takes a long
time to produce an image — from an hour to a day is typical for a
non-trivial scene rendered on a fast Amiga. Another method is called
scanline rendering, which still gives you the perspective, transparency and
illumination effects, but doesn't take into account refraction or the
reflections of objects onto one another. (You can have objects reflect a
"world map", an image of the environment such as clouds and ground, which
gives you a more realistic picture) Scanline rendering is much faster than
ray-tracing, and thus more often used.
Blaq!
Blaq,
Thanks for the info. I need basic info like that so I can sift out the
claims of the various software packages.
This may seem like a dumb question, but can Imagine take an imported image
(say, a figure), alter it somewhat, and then slice it up even if was not
originally constructed with slices?
Also, what would your minimum hardware requirements be for someone getting
started in this field? I have a stock A2000 with a hard drive and 3 megs
of ram, but I'll be upgrading with some sort of accellerator board soon.
Any comments are welcome.
Thanks,
Lee
Lee,
3 Megs of RAM and a hard disk is, indeed, the minimum. You'll want that
accelerator real quick. B^) As to your other question, Imagine supports
Boolean operations, where the program detects the common parts of two
objects. You can then delete the pieces you don't want; for example,
applying the "Slice" command (that's what Imagine calls it) on an
intersecting plane and sphere will result in 4 objects: two bowl-shaped
objects (formerly the sphere), a flat circle (the part of the plane inside
the sphere), and a plane with a circular cutout (the part of the plane
outside the sphere). You can discard the pieces you don't want, and perhaps
merge the rest. You could apply this method to your imported object by
slicing it with a horizontal plane close to the top and saving the relevant
part; repeating the procedure with lower and lower planes will eventually
result in a disk subdirectory filled with the slices you want.
Other programs support this type of slicing. The keyword to look for in
ads is "Boolean".
Blaq!
Blaq: thanks for the information; learning the vocabulary of this field
is the first step. ——Lee