transparency problem

[nickname7]

i'm having problems with transparent models in shockwave...

i have several plane models with transparent pngs, for example trees and
fences. when i move, sometimes the farther model is in front of the closer
model (oh, my english, sorry, hope you understand what i'm trying to say...)
etc... i tried several settings (shaders, textures, cameta etc) to avoid this,
but nothing worked... so i googled and found this in a lightwave forum:

"This is not a lightwave issue but rather a Director 3d issue. Director must
calculate depth sorting based on each models pivot point, therefore, when you
use a transparent texture on a mesh there is no way to tell what polygon is in
front of another polygon. This is not a problem so long as there are no
transparent polygons in the mix, but as soon as you start introducing polygons
with texture based alpha, the entire mesh goes crazy. I'm not completly sure if
this is indeed the situation but I have found a few fixes that lead me to
believe that it is.
1: use shader based transparency instead of texture based transparency. You
have to make the polygons that need to be transparent a seperate shader and
then adjust each shader's transparency value. this works great for things like
vehicle cockpits, windows etc... but still might not completely do the trick.
2: make each polygon that needs to be transparent a seperate model. This
method works really well and you can continue to use texture based
transparency. I use this method for fences and things often. Also try mixing
the above fix and this one together.
I feel your pain on this issue man. This is the single greatest defect in
Director's 3d engine and I really hope they fix this before adding more silly
upgrades like mx.
good luck!
PS
I've tested the transparent problem in virtually every exporter on the market
and all of them had the same result "

is there any way, any workaround other than this to get things working? i have
no idea how to get the results i'm looking for...
thanks in advance

[necromanthus]

As I said many times before:
you have to detach the transparent pieces (models using alpha-channel textures) and to center the pivot for each one !
cheers

[nickname7]

hi necromanthus,

i know what you said -
[url]http://www.macromedia.com/cfusion/webforums/forum/messageview.cfm?catid=268&thre[/url]
adid=896864 - but i get the problem with lingo generated models...
i also tried with exported w3d file (very simple, just a horizontal plane and
some vertical planes( trees and fence), the pivots of the models were all
centered...
hmm, i'm confused, maybe i get something wrong...

thanks anyway

[nickname7]

hmm, i guess i'm having problems to explain what i mean... necromanthus, the
topic was about (complex) models and transparency and you said one has to
detach the transparent part etc, pivot etc...
now i found that this problem occurs even with simple planes and transparency.
i uploaded a file at:
[url]http://malon.de/[/url]

maybe you can have a look? move around (arrow keys) and you'll see that
sometimes the palmtree gets in front of the fence and the fence in front of the
palmtree, when it shouldn't...
i would very much appreciate any help, as i feel like being unable to see the
woods because of all the trees (don't know the english equivalent, in other
words, i'm a little frustrated, confused, whatever...)

thanks alot

[nickname7]

the starting point is a little stupid...

move backward (down key) at start...

[hondo3000]

i believe your problem is the fence which is very long. so whats wrong with the
fence? the centerpoint of the fence is used to calculate the z-order for
transparent models, and sometimes you are closer to a tree then to the fence.

i am sure this happens only for transparent models. but i am not an expert,
its just a idea that came to my mind when i was testing your scene.

i would run a littel script that mesures the distance of the three models and
have a look at the distance to the camera and the z-order.

i would take more smaller fence peaces may be at the same dimensions as the
trees and have a look if the problem is still there.

hope it was helpful.

[necromanthus]

I can't find any viewing bug there ! (FX5600).
Do you own Radeon Vcard ?
That's because several viewing bugs were reported for these cards.
cheers
Originally posted by: nickname7
[url]http://malon.de/[/url]
maybe you can have a look?

[nickname7]

hi hondo, thanks for your reply!

i think you're absolutely right.
the basic idea was to find a way to build a landscape, a park, a town and so
on with a theatre like scenery (?) made up of more complex models created in
c4d and many planes with simple textures like bushes and trees and distant
hills, whatever...
so the whole thing would become pretty complex and i thought (hoped) this was
a possibility to get a cool visual effect with less polys... also i wanted to
limit the area the user can move, so walls and fences and so on would be the
right choice.
i tested so many different things the last two days that somehow i lost track
:-(

Originally posted by: hondo3000
... i am sure this happens only for transparent models.

and yes, it only happens with transparent models. if for instance the model,
which is now the fence, is a box, everything is okay.
you can test here: [url]http://malon.de/sample2.html[/url]

press "1" which turns the blend of one shader of the box to 0, "2" turns it
back to 100...

but you can imagine that it doesn't make sense this way with a load of
different models and not just three like in the sample... i think i have to
model all the stuff like trees etc... i wish i had a little more experience and
i wish i could spend more time on shockwave but unfortunately i can't (at least
at the moment)... right now i'm just trying to find out what the possibilities
are...

thanks again, regards

[nickname7]

Originally posted by: necromanthus
I can't find any viewing bug there ! (FX5600).
Do you own Radeon Vcard ?

bingo! ati rad9600 xt...

hmm, this is strange, didn't know about it. don't know if i should be happy
now... i think i am... thanks for your reply necromanthus. you can see what it
looks like here:
[url]http://malon.de/pics.html[/url]

can you give me a hint what to do? i tried to explain above what i'm looking
for.
i think the idea itself wasn't too bad...

thanks and regards

[necromanthus]

I don't know what you're doing wrong there, but for fences (planes) or boxes is
the same rule.
You'll find a lot of fences in
[url]http://necromanthus.com/Games/ShockWave/heretic.html[/url] , but there're no viewing
bugs at all !
All you have to do is to center the pivot for each fence (plane).
cheers
Originally posted by: nickname7
it only happens with transparent models. if for instance the model, which is
now the fence, is a box, everything is okay.

[nickname7]

Originally posted by: nickname7
it only happens with transparent models. if for instance the model, which is
now the fence, is a box, everything is okay.
yeah, this is not correct. to be more precise: "if for instance the model,
which is now the fence, is a box, and its shaders are not transparent
everything is okay... if one shader is transparent it is not... " this is at
least what i experienced... but of course i hope, it's like you said, it's the
vcard. i'm trying to get some info on the bugs you mentioned...

regards

[hondo3000]

i made a test on my own and came to the same result:
for transparent models the z-order is calculated by the distance to the
camera. i made the test with cinema4D and some transparent planes that are
close together.
you can see the test here:

[url]http://kisd.de/~lutz/3dtest/transparent/[/url]

all pivot points are centerd. if somebody can show me a different result, post
it here and tell me how its done.
i think transparent models need some
greetings.

[ccloveaa]

i have a question worried me a long time ,i found more than two transparency
object superpose ,the problem will happen,the transparency objects looks very
strange ,how can i solve it?
i try some way to solve it ,ungroup,center the object's pivot,but the error
still occur.
how can i solve it? thanks a lot.
here is my sence
[url]http://vip.5d.cn/ccloveaa/tc.rar[/url]

[Michaelcov]

Try ungrouping everything then group everything into one single group.

It's not perfect, but seems to solve most of this for me.

Michael
UK

[necromanthus]

Originally posted by: ccloveaa
i try some way to solve it ,ungroup,center the object's pivot,but the error
still occur.

Michael gave you a good hint, but it's not enough in some cases.
Transparency in ShockWave is a real pain (because of the its primitive
Z-buffer structure).
As general rule: do NOT use alpha-channel textures for complex meshes
(models), because centering the pivot is almost worthless on these models.
Use them for simple models such as: walls,windows,fences,etc (few polygons per
model).
To get the best results: no more than 2 polygons per "transparent model"
(don't forget to center the pivot for each one).