.3ds models and emissive maps

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Reiko
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.3ds models and emissive maps

Post #1by Reiko » 13.12.2011, 22:30

Is there a way to make emissive maps work in .3ds models? When using Anim8or I place them and make sure the emissive value is set to 1. However they do not work in Celestia. Does the .3ds format not support emissive maps or am I doing something wrong?

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selden
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Re: .3ds models and emissive maps

Post #2by selden » 14.12.2011, 21:23

My understanding is that 3DS meshes don't support emissive maps.

However, CMOD meshes do support emissive maps, and the CMOD export plugin that I wrote for Anim8or will specify them if they're declared in a material definition. You also can use Anim8or's point editor to make regions on a surface emissive without an emissive map.

A description of the CMOD export plugin is available at
http://www.lepp.cornell.edu/~seb/celest ... g.html#4.1
Selden

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Re: .3ds models and emissive maps

Post #3by Reiko » 14.12.2011, 23:09

I'm familiar with CMODs and the script for Anim8or. In fact that is what I use most of the time. I was wanting some of the models in 3ds format because they can cast shadows. For some reason CMODs cannot produce shadows.

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Re: .3ds models and emissive maps

Post #4by selden » 15.12.2011, 12:59

I can think of a couple of ways it might be done with two separate models, although neither of them is entirely satisfactory because of depth sorting problems.

Method 1: Its difficulty depends on the complexity of the model. One copy of the model would consist only of the parts you want to glow. The other would consist only of the parts that you do not want to glow. Then, specify Emissive true for the glowing model. Use the SSC to place the two models at exactly the same polsition so that the holes in one are filled in by the other. Cutting a complicated mesh into many pieces would be a *lot* of work, though.

Method 2: Its difficulty depends on the complexity of the surface texture images. One model would have a surface texture image (or several) that's opaque or translucent where you want it to glow and transparent elsewhere. (3DS does do transparency.) Specify Emissive true for the glowing model. The other model would be painted with opaque surface texture images. Make the model that will be glowing very slightly larger than the one that does not glow.

A combination of the two methods might work, too.
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Re: .3ds models and emissive maps

Post #5by Fenerit » 15.12.2011, 15:17

Reiko wrote:I'm familiar with CMODs and the script for Anim8or. In fact that is what I use most of the time. I was wanting some of the models in 3ds format because they can cast shadows. For some reason CMODs cannot produce shadows.

Does the CMODs have normals and tangents?
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Re: .3ds models and emissive maps

Post #6by Reiko » 17.12.2011, 06:19

Selden, it didn't occur to me to make a combo model part 3ds and part CMOD. I'll have to give that a try and see how it comes out. :D

Fenerit wrote:Does the CMODs have normals and tangents?
I don't know about tangents but they do have normals.

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Re: .3ds models and emissive maps

Post #7by Fenerit » 17.12.2011, 12:23

Reiko wrote:Selden, it didn't occur to me to make a combo model part 3ds and part CMOD. I'll have to give that a try and see how it comes out. :D

Fenerit wrote:Does the CMODs have normals and tangents?
I don't know about tangents but they do have normals.
Sorry, I'm out from my computer for experimenting with. There isn't reason why 3DS would cast shadow while CMOD not. 3DS saves tangents by default while for CMOD the option is left to the user; you can try to make CMOD's tangents with the CMODview utility. Tangents usually are required by vertex shaders, albeit could be avoided under certain circumstances. The file size will be more heavy, of course.
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