#RENDER SPEEDUP
34 messages in this thread
GARY;
I'll bet this is not a new idea.
I was watching my animation of a LOGO render today and am always wanting
things to go faster naturaly…. so I wonder how difficult it would be
to write the code to make 3D Studio render only lines that are different
from the last rendered image? Many of my animations involve a large part
of the whole screen that is the same as the previous image except for
one small portion that is changed.. Couldn't the program be written to
simply duplicate each previous image and then write over only the part
that is different. This would really speed things up…. -David R. Long
There are already many optimizations in 3DS for elements of scenes that
don't change, but what you're talking about is quite a bit more complex
than you might think. (In fact, there are no rendering packages that can
do that.) This is because things like shadows and reflections are highly
inter-object dependant.
There IS a way for you to use Video Post to make your rendering process
incredibly efficient, compared to raw rendering of entire scenes. Just set
up your scenes as VP layers, and when you need to make a change to a layer,
all you've got to do is render the objects on that layer. Martin Foster
utilizes this technique heavily, and it saves him HOURS of time. He'd be a
great person to ask about specifics.
– G
Re: Video Post layering to facilitate render speedup.
Yes, I do and yes, I would <g>.
If anyone wants to know specifics they can ask. I also use this method to
correct mistakes – for instance, if an object is not to my liking no
problemo, I just re-render the object against a black background at 32-bit
and composite it back to the image in video post making sure that the
field/frame mode and anti-aliasing levels match, of course. If there are
objects between the one I'm redoing and the camera I can render them as
well (in the case of anything with transparency/opacity maps) or make them
mattes with a flat material for fast rendering.
This technique has saved my derriere (can I say that on CI$?) on more than
one occasion (Greg Pyros may recall an occasion) when others would simply
have rerendered the entire, blooming scene (pardon my French, again).
Martin,
Glad to hear I'm not the only one who hits the wrong buttons . . . yes, I
know about the .bak file — I'm glad its there.
Question about your re-rendering over black video post techniques: Am I
correct in believing that it can't be used if the camera (and the
backround) is in constant motion?
Alec Jason
Alec:
You can use the technique ANYTIME, with the obvious exeption of when an
object passes _in_front_of_ the object you are trying to correct.
But this is solved by just re-rendering both objects.
Make sure you have 2.0 or 2.01a to do the compositing, though! Not 2.01!
Greg Pyros
Greg,
Thanks for the tip. But to make this clear to myself; are you saying that
if I have two human figures walking around a room while the camera moves as
well, I can composite render one file with just the room and the furniture
and one file with just the people?
Alec Jason
Alec:
Sure can!
1) Render the first pass with just the room, and save the files. You do not
need to have alpha on for these files. Could be fli or targa.
2) You can do this in 2 passes or three, depending on your whim. I'll
describe the 3 pass method. It takes the same amount of time, but
creates more files. I prefer it, because I feel like I have more control
of the process, and if there is a glitch, it is easier to fix.
3) Render the two people with no background and alpha on (could use
alpha-split, but unless there is a specific reason, I don't recommend
it). This must be saved as a 32 bit file, fli won't work.
4) Now just use video post to composite the two images together using the
alpha in the targa files. Done!
Just make sure your camera moves are such that you don't have the people
passing BEHIND objects that were rendered in the background!
This way you can render the images, have the judge throw them out, and just
re-render the objectionable part again. The composite in video post is very
fast – only a few seconds per frame.
Greg Pyros
Of course, you won't get shadows or reflection maps to work this way, but
Alec probably isn't too concerned about that. I've talked to Gary about a
pseudo "bluescreen" effect whereby you could render your people against
bluescreen type objects thereby preserving shadows and then composite your
image with the transparency being the colour value of the "bluescreen"
object. Right now it's RGB 0,0,0 only but this could easily be changed to
any colour value you selected, IMHO. Don't know what Tom and Dan would have
to say about that but I think it would be a totally brilliant ability. What
do you think, matey? Knowing you, you've probably flowcharted and spec'd
out this capability already <g,d&r>
Martin "name-dropping with the best of 'em" Foster
Martin:
If you could bluescreen that, you could animate the weatherman, also! <g>
Especially in the summer here in southern California where it never changes!
Greg
I was thinking of more, ahem, creative animations <g>.
Greg,
Verrrrry interesting. I didn't think it would work. The composite method
will sure help me out with changes in the action.
Thanks again,
Alec Jason
P.S. Here's a question you might be able to answer: A friend of mine is
looking for low cost and relatively simple program which would enable him
to quickly draw overhead-view room or apartment drawings with ready made
furniture symbols. Do you have a recommendation?
Alec:
Try something like Generic CAD or AutoSketch. They will also export DXF
files so that you can take output into AutoCAD or 3DS.
Available at our local Egghead / Computer Warehouse for below $400 / 200.
(oh, it HURTS for a dealer to say that! <g>)
Greg
Thanks Greg, but he's looking for something simpler than cad type programs.
(He's not "one of us" . . . well, one of you!)
Alec Jason
In addition to Generic, Autodesk (through Generic) also publishes "The Home
Series." This is four separate programs, titled Home, Kitchen, Bathroom,
and Landscape. They let you easily create floorplans and elevations of
their described areas. Get Landscape, for example, if you want to design
gardens. I played around with one of them, and did a design for my kitchen.
(No kitchen, yet, just a design…) Anyway, it provided a relatively easy
way to lay down the dimensions, plus a library of cabinets, refrigerators,
etc.
I have no idea of the cost of these things, or where to find them. They're
a retail product and shouldn't be too much. The number on the box is
800-2283601.
– J
Thanks Jack. I think he tried one of the retail Autodesk products and
didn't like it for some reason. I'll have him call and find out more.
Alec Jason
>> quick office planner
In this months Cadalyst Mag, there is a review of some Facility/Space
Planning programs (our FAC-MAN happens to be one of them). One of the
packages mentioned was called "Easy Office" or something. It runs outside
of ACAD and seems really powerful. The review was so impressed with it, he
dedicated a two-page "side bar" spread to the program. As I remember, it
was under $500.
Ang
Thanks Angelo, for your help. I'll read the articles you mentioned. But my
friend wants something SIMPLE. He doesn't need DXF files or anything fancy.
He is not and does not want to become what Gary calls a "mutant high
priest of computer graphics and animation" (something like that.)
Alec Jason
Alec, it's just "mutant computer graphics priest". <g>
– G
Alec,
no moving makes no difference, it's effective at any time, just don't
forget to include objects that become between the camera and the one you
are re-rendering. Like I said the ones that come between can have simple
flat material applied with no texture map and change it's attributes to
MATTE object – this will give you the desired outline but render that
object faster than if it had texture maps and phong shading applied to it.
This makes it invisible to the alpha channel but it will mask any objects
going behind it. To see an example of this render one frame with at 32-bit
with alpha-split on and then look at the main 24-bit image where you will
see all the objects you rendered and then look at the 8-bit alpha channel
file where you will see a "black-hole" where the matte object's outline is
blocking any object behind it. However, if the object uses an opacity map
you might be better off rendering it the way it was before without changing
the material or attributes (I'll check this theory).
Martin, you and Greg are providing EXCELLENT information here! Really
fantastic stuff… Thanks to both of you!
– G
Gary:
Why, thanks, golly gee, shucks, and you're welcome! <blushing in modesty!>
Greg
No no no no…. Thank YOU!
– G
This is great stuff. Can I put some of this in the release 3 docs?
– Jack
You can put my stuff in the doc's for the price of a credit. Something like
"special thanks to Martin Foster and Greg Pyros for video post power tips"
at the beginning in very small type would be appropos <g>.
Martin:
We can always ask, can't we? <g>
Greg
Doesn't hurt to ask (I hope) <g>.
If you'll notice, I can't even get _my_ name in the docs as a credit. We
managed to get credits for the team into the original printing of the
Animator docs, but then the corporate Autodesk mind took over and banished
even those. Maybe I could slip you both in by naming a couple of materials
after you, and then adding them to the tutorials:
1. Assign the Martin Foster Matte to the sphere, and the Greg Pyros Phong
to the torus.
Waddya think?
– J
OK, but Adesk would probably notice and veto it <g>.
Yes, and a bargain at the price, too! <g>
You're welcome. The information is a real bargain at the price, again <g>.
Really… Such a deal!
– G
Correction to my last message. If you make an object a matte object because
it comes between the object you want to re-render then you would NOT need
to change the material – just changing the object's attributes to MATTE
will suffice. The matte will appear as a black hole in the 24-bit image and
the 8-bit alpha image whatever kind of material is assigned and be
invisible when compositing. Mattes seem much faster than regular materials
since no shading, texturing etc is involved. You still can NOT use them for
objects with opacity maps, though.
Martin,
Thanks very much. I'm going to try your suggestions.
Alec Jason
You're welcome and good luck.