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Transparent water

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Helvene
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Joined:  Sun Mar 05, 2006 5:31 am
It's quite a common mistake in NWN modelling, that placeables or tilesets makers consider that if they have a transparent or semi-transperant testure, it is enough for making a transparent water layer or something alike. It's not so. Non-white alpha channel works well for other placeables or parts of tileset which are supposed to be under the water layer, but doesn't work at all for PCs and creatures.

It can be seen on the first picture (transparentwater1.jpg): the girl there is standing in a pool, and the water there "cuts off" everything which appears to be under it.

The problem is solveable by making an additional dummy in a tile and linking a water layer with it, and not directly with the model base. It's important that only the parts of the tile which are supposed to be transparent are linked to that dummy.
The hierarchy the same as shown on the second picture (transparentwater1a.gif): red is a modelbase; pink is an additional dummy; blue is a transparent object; black are links, green are names in the tile I modified to get the examples.

If everything is done in a proper way, in the end we'll get the same picture as shown on transparentwater2.jpg (it's a third picture). Notice that not only the water is really transparent now, but it's color is also slightly different.
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Aedrielle
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The colour is different because light is actually passing through and a creature shadow is also cast on the ground underneath, not on the water surface, as before.

Actually - the first 'broken' model looks very good, if water is supposed to be murky ;)

[Is this something new? I thought it to be a known and documented feature...]
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Helvene
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Aedrielle wrote:[Is this something new? I thought it to be a known and documented feature...]

{I also thought it was until I found non-transparent placeable water in CEP}
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Chandigar
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Yea, full transparencies seem to work ok as part of a tileset model, but partial transparencies is where is starts to get messed up. PC models, most animated stuff, and other transparencies seem to vanish when seen through a semi-transparent texture.

There might be more restrictions, but I"m not sure yet... I still haven't tried linking all of a layered transparent object to an animation node to see if all the transparencies work yet.
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Helvene
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Joined:  Sun Mar 05, 2006 5:31 am
Chandigar wrote:Yea, full transparencies seem to work ok as part of a tileset model, but partial transparencies is where is starts to get messed up. PC models, most animated stuff, and other transparencies seem to vanish when seen through a semi-transparent texture.

Well, thу method I described solves this problem.

Chandigar wrote:There might be more restrictions, but I"m not sure yet... I still haven't tried linking all of a layered transparent object to an animation node to see if all the transparencies work yet.

No idea. I've never worked with animations.
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Chandigar
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Helvene wrote:No idea. I've never worked with animations.


Err.. your "a" dummy is called the animation node, officially (I believe). Thats all I meant.
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Helvene
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Chandigar wrote:Err.. your "a" dummy is called the animation node, officially (I believe). Thats all I meant.

At least, in all official sets water is usually linked to this "a dummy".
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lord rosenkrantz
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Joined:  Sun Aug 21, 2005 6:46 pm
Yep, Chandigar means that the "a" dummy stands for "animation" dummy, as per official NWN engine standards.
Apparently transparencies are better handled by the engine when they are linked to this "animation" dummy, I guess because the engine render them better than normal meshes (which likely was done to optimize the engine and not to waste processing power on rendering normal meshes more than what was necessary)
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Guest
FYI the a dummy is also useful in placeables.

The translucent curtains and stained glass panels I made for Castle Interior Windows for example, use the a dummy to prevent the screens from cutting off other creatures and animated objects (such as the skyboxes).

Basically, the a dummy is the quick and dirty solution to many transparency and alpha problems.

You know how people complain about the white edges thing on foliage and trees. The a dummy can fix that too.
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Chandigar
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Joined:  Fri Apr 01, 2005 6:00 pm
The way its been explained to me is basically, if its not hooked to an "a" dummy, the engine renders it once and reuses the information to display the object, which saves processing power.

If its hooked to an "a" dummy, then it recalculates it each time which makes it much more processor intensive, but you get a much better effect... too many things hooked up to it though, and you'll get a visible performance hit.
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