Jan
I tested the latest vrml plugin on some larger files, real vrml files rather
than the little test files that I sent you before. I tested them with both
osgviewer and vrNav2, my own program. First, the problem with
osgUtil::SceneView crashing in draw( ) that I had before when I loaded the
vrml files with vrNav2 is now gone, so that's good. I notice, from looking at
the resultant .osg files, that the vrml translation is introducing a rotation
to turn the z of the model up. vrNav2 already does that for all models so I
added a test there not to do it for .wrl models it loads. The first few
models that I loaded worked fine. Then I ran into a problem. The problem
seems to be related to the size or the number of Shapes in the vrml file.
Also, it may be some kind of timing problem (in it taking too long to load the
model).
The problem manifests itself as follows: in osgviewr, the graphics screen
comes up as a black screen and then turns into a screen with a blue background
and the model appears. With the ones that don't work, the screen remains
black and you don't see the model. With vrNav2, vrjuggler is opening for me
(using X Windows calls) a black graphics screen of size 640 by 480. With the
ones that don't work, I get a black graphics screen that fills the whole
screen (not 640 x 480) and no model. When it works, I get my 640 x 480
graphics screen. vrNav2 writes out the model's bounding box dimensions
immediately after loading the model and this always happens. Also, if I
change the vrNav2 code so that immediately after loading the model it writes
out the model in .osg format, the problem is gone and the program work and the
problem. But if immediately after loading the model, I just add some sleep, I
am back to it not working.
If I take a model that doesnt work but which has multiple Shapes, and divide
it into .wrl files each with a single shape and load just a single Shape, it
always works. I can also take subsets of the Shapes and have it work.
Here are 4 models:
waves.wrl with 3 Shapes 3406099 bytes
isos2_2.wrl with 2 Shapes 883264 bytes
sigmoid.wrl with 6 Shapes 326260 bytes
vectors.wrl with 8 Shapes 3234335 bytes
>From them I constructed the following: sigmoid1.wrl the first Shape from
sigmoid.wrl, sigmoid2.wrl the second Shape, ... sigmoid6.wrl the sixth Shape,
sigmoid1-3.wrl the first three Shapes, sigmoid1-4.wrl the first 4 shapes,
sigmoid1-5.wrl the first 5 Shapes. vectors1-4.wrl the first 4 Shapes from
vectors.wrl, vectors1-5.wrl and vectors5-8.wrl etc. waves1.wrl the first
Shape from waves.wrl, also waves2.wrl, waves3.wrl and waves1-2.wrl.
Here are the results:
model vrNav osgviewer
----------------------------------------------------
sigmoid black screen black screen
any of sigmoid1 through
sigmoid6 works works
sigmoid1-3 works works
sigmoid1-4 works black screen
sigmoid1-5 black screen black screen
isos2_2 works works
waves black screen works
waves1 black screen works
waves2 works works
waves3 works works
waves1-2 black screen black screen
vectors black screen works
vectors1-4 works works
vectors1-5 black screen works
vectors5-8 works works
Anyway, I am not unhappy with this situation. My goal is to be able to take
vrml 2.0 files output by scientific visualization programs and turn them into
models that can be loaded. I can easily do this by following this procedure:
osconv whatever.wrl whatever.osg
edit whatever.osg and remove the matrix transform at the top
osconv whatever.osg whatever.ive
Then I load the .ive file and that always works.
I also tried writing a vrml 2.0 file from VMD a popular program used to
visualize chemistry molecules. That program wrote out an absolutely huge file
with one Shape per triangle. That file can't be loaded. However, I can write
a program to read in the vrml file as output by VMD and convert it to a more
reasonable one that looks like the vrml files output by OpenDX. I did some
playing around with that and that will also work.
Joan Slottow
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