#rendering problem
7 messages in this thread
3D Studio Rendering problem
A corner of a room. A rectangualr wall object built with a box, with planar
mapping
Coordinates and a 24bit TGA texture of bricks, intersects in 60 degree angle
with
another wall of the same characteristics and a floor object built by getting a
shape
from the 2D shaper. A 30 mm camera runs parallel to the contiguous wall.
When rendering this simple animation , on some few frames, the texture map of
one of
the walls appears distorted as if it had been pixilated or boxilated. It only
occurs in
one of the walls and only in some frames of the animation, as if the distortion
was
related to the angle in which the camer is targetting the wall. There does not
seem to
be a specific patter to the relation between the camera angle and the wall.
This
corner situation is repeated in several places within a model. Depending on the
specific corner location we get different variations. In some corners there is
no
problem at all. In some corners the distortion occurs at the beginning of the
turn,
when the camera is perpendicular to the wall, sometimes it occurs in the
frames
when the camera is turning and the wall gets very close to the camera and
sometimes it
occurs at the end of the turn when the camer is parallel to the wall.
Any explanation?
we can provide example images if necessary.
These problems have been noticed in version 2 as well as 3.
Adrian Cook
ajc@epic.co.uk
Adrian,
Do the faces you see this problem happening on by any chance share the same (or
close to the same) space as a face (or faces) from another object? For example,
do your walls intersect in such a way so that some faces may be (or are very
close to being) co-planar?
If this is the case, move the objects away from each other (at *least*) a
couple of hundreths of a coordinate and render again, as the renderer needs to
be able to discern exactly which face to render, and if they are too close
together, it can get fooled.
This is just a "shot in the dark", so to speak. I hope you find the problem.
-Alan Iglesias
Thanks Alan,
I have just checked the object and it has no co-planar surfaces that are
below about 10000 units apart from each other. This has raised the question
about the scale of our objects. They are massive, this 10000 units is
the width of a bounding wall so the bounding scene rectangle will be
about 1000 times that.
Any other ideas?
Adrian Cook
ajc@epic.co.uk
If your objects are TOO large, then they'll overrun the floating point accuracy
for the mapping coordinates. Try rescaling the scene to real-world
coordinates, then reapply mapping coords and see what happens.
– G
Gary's ideas about scale, of course, are good things to try.
I'm afraid there's not much more I can think of without seeing the file,
though.
Hope you figure this out,
-Alan
In addition to what Alan mentioned, there are a couple of dozen different
"no-no's" that could be going on in your scene that might cause those kinds of
artifacts. Most of them relate to coplanar geometry, overly large or overly
small mapping coordinates, or a combination of the above. Without actually
seeing the room model, I can't tell you what you're doing that's causing it.
If you'd like to zip the file up with the maps and a text file explaining
exactly what to look for, you could send it to me via binary email and I'll
take a look at it for you when I get some free time this week.
– G
Is what you are describing situations where the walls (and thus mapping) are
being distorted due to the focal length (w/a) and camera/object position ? If
so, use a much higher res. map and/or stronger filtering, perhaps summed area
mapping. It's hard to tell if this is what you are describing.
BILL