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smoking plane
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rich0e0rick
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Question smoking plane - 09-11-2008, 04:41 PM

does anyone know how to make smoke that would follow a plane (trails after it) but that doesn't have any invisibility (less than 95%) and doesn't have a skin that has any see trough (like the SMOKE animation"s edges)?

i cant use any opacity because when you put lets say a square of 0% in front of another square that's only 60%, u can see where the first one is (the "shadow" of the first square is on the other, makes the second one look like theirs a hole in it... p.s. you have to be far away from the objects to notice this sometimes...)

it only seems to happen in larger files, because it didn't do it when i tested it in new worlds... only in my larger ones...


so i repeat my question... does anyone know how to make smoke that would follow a plane, but of which the smoke has no opacity below 95%...or none at all hopefully...

Thanks in advance for any help.

rick
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Alpha channel transparency
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DrJim
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Default Alpha channel transparency - 09-12-2008, 01:46 PM

This may be much more of an answer than you had in mind - but this is one of the few areas that Alice can really compete with dedicated graphics programs - largely because of the many options available for use in your own methods.

It may also not specifically address your question about file size dependence. That's not something I've seen.

But basically the key is to use an image or a series of images in .png format and with "alpha channel" transparency. The "alpha channel" is just an additional 8 bits of data beyond the normal RGB data - I won't even try to explain the details, but most advanced graphics programs will automatically take care of that for you. (An exception is if you are seriously using CMYK color - the conversion may not be what you want - but doubt this is an issue for most Alice users.)

Once you get the image with transparency, you can either import it as a billboard (2D) or a texture for a simple shape (3D). From there - your own creativity is the limit. See the special effects objects in the gallery for other ideas.

I've attached an image and a very simple example. (I had to upload this as a .zip file since the .png file uploaded as .jpg, which may not have the right transparency,)
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???
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rich0e0rick
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Exclamation ??? - 09-15-2008, 05:40 PM

i figured out it has to do with the objects distance to the camera and the camera's angle...

as for your example, don't forget, the ground is supposed to be 60 or 70% opacity... use your example, put the ground at 60%, then drag the smoke around a bit(u might have to back up as well). does it do the same to you?

As for your .png, it only works about the same amount as the normal smoke...
is there a way i can get a 3d smoke that animates(without having to put 100objects together and make them move in a pattern)?

rick
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Last edited by rich0e0rick; 09-15-2008 at 05:43 PM.
   
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DrJim
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Default 09-16-2008, 05:12 PM

Quote:
Originally Posted by rich0e0rick View Post
As for your .png, it only works about the same amount as the normal smoke...

Is there a way i can get a 3d smoke that animates(without having to put 100objects together and make them move in a pattern)?

rick
For 2D smoke/explosions, there are several freeware programs that will give you more complexity than the "smoke effect" from the gallery. Do a Google search on "explosion generator software." One I particularly like is explogen, http://www.kenginegaming.com/explogen2page.php . The basic effect will still be 2D and a sequential list - but you can get rather interesting patterns.

For 3D - I don't know of a way unless you have lots and lots of hardware - and money. The problem is that most 3D objects are just meshes and surfaces - not really solids. Doubt that you need 100's of objects - but problably at least half a dozen.

What I would (and have) done there is to mix a smoke video with the Alice animation using a video special effects editor such as Wax, http://www.debugmode.com/ . It's a lot easier to get realistic smoke just by photographing a smoke source than to try to simulate it.
   
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but
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rich0e0rick
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Question but - 09-16-2008, 06:23 PM

but wont the 2d smoke do the exact same thing the smoke already furnished by Alice does(the "hole")?

ill try them anyways... if it doesn't work, ill try for the 3d, maybe i can make some in anim8or somehow...

thanks

rick


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2d
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rich0e0rick
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Talking 2d - 09-16-2008, 06:39 PM

your 2d wont work because it has a background to it... i would have to manually change 65 pics to png format, and then test every one, not a fun prospect for something that might not work... ill try the 3d wax next, thanks a lot for your help... hope THIS works...

EDIT: is there a way so i can make the .avi have a transparent background? its the only format


rick


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Last edited by rich0e0rick; 09-16-2008 at 06:49 PM.
   
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.png batch file conversion and .avi transparency
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DrJim
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Default .png batch file conversion and .avi transparency - 09-17-2008, 08:16 AM

There are several programs that will do batch conversions, including transparency. My favorite is IrfanView, http://www.irfanview.net/ which is, in addition to the conversion feature, quite a nice viewer in general.

I've also used a very nice .gif editor I think will do this - http://www.benetonsoftware.com/ . Don't have it on the machine I'm using right now so not 100% sure about the .png part - but if you work with .gif, I recommend it anyway.

Re transparency in .avi format - that's a CODEC issue, but transparency generally isn't supported directly. You can get the same effect with an editor (i.e. Wax) and the chroma mix function (also known as blue screen or green screen) - in this case you have to have your object against a solid color background and then mix the image with a second background image. Wax documentation is weak to non-existant but there is a lot of information on the web since the technique is used by nearly every TV station in the world.
   
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Second Thoughts
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DrJim
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Default Second Thoughts - 09-17-2008, 02:28 PM

After posting the preceeding, I had a couple of second thoughts on the appropriateness of posting it here. Although I enjoy this type of thing - it is pushing Alice way beyond its intended usage.

Really using some of the tools, especially Wax and the related WinMorph, is more a subject for a video graphics/editing course - not one for OOP.

I don't mind answering these questions here. From people that teach those subjects, I hear that programming concepts are big stumbling blocks - particularly Action Script - for the more "artistic" types that take those courses (not a snub - one daughter has a BFA and the second a MFA degree and both are far better at programming than I am as an artist) and I think Alice could help. I will try to reply in the "Work in Progress" section rather than this one, however.
   
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