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2 sided normals

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I want to create Models that have double sided normals, and then export them via the obsidian plugin to an *.x file for direct X, Can this be done? I have seen others ask this question, and I do not recall the outcome for them. My current method is to create a duplicate models and shrink them slightly and flip their normals to have a back side. This is a fine work around, ecxept for the fact that this doubles the amount of CP's in my X models, and thus is slowing down my renders considerably, especially when I have a lot going on in my game.

 

I have seen other games use double sided normals, and I assume they have proprietary engines that do this, is this true? Or can AM emulate this as well some how some way?

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I want to create Models that have double sided normals, and then export them via the obsidian plugin to an *.x file for direct X, Can this be done? I have seen others ask this question, and I do not recall the outcome for them. My current method is to create a duplicate models and shrink them slightly and flip their normals to have a back side. This is a fine work around, ecxept for the fact that this doubles the amount of CP's in my X models, and thus is slowing down my renders considerably, especially when I have a lot going on in my game.

 

I have seen other games use double sided normals, and I assume they have proprietary engines that do this, is this true? Or can AM emulate this as well some how some way?

 

Short answer is no to the best of my knowledge (I asked this before)..........

 

Sorry

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Double side normals doesn't make sense to me. A normal can only point in one direction and the reverse normal, if you really need that would be the normal negated. No real need to store that since this is implied. I would guess that for a game engine to display back facing polygons, you would need to specify that it just should render back facing polygons.

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I never had the need to view the back of a polygon. Your best bet is to create a solid brush like a cube. You'd never want to render backfacing polygons; that would literally double the render time. When creating your models, just make sure that what you want to be visible is visible in reference to the normals.

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I once needed to do this. You don't need 'double sided normals', but 'double sided faces'.

 

In poly (game) world, polys are almost always one-sided. I think back-face culling is always ON in game engines, so there's no use for turning it off in A:M (default key: shift-6 will show backfaces on/off).

 

You are mostly right on your method. But it should be used to specific parts of a model and not the whole model. Your models should be always closed-meshes, with no backfaces.

 

But, say you are modeling a tree with foliage. In this case, the tree trunk should be a closed 'mesh', and the foliage, just some flat 'patches'. Then, you want to duplicate all the foliage patches and FLIP the normals. But - DO NOT move the CPs, nor slightly. Leave them on the same place.

 

It's better that you UV-MAP (decal) the patches before duplicating. This way you'll get both the front and back patches textured correctly. And most .x importing apps (fragmotion, 3dgs...) will be able to weld the duplicate CPs (vertex) into one, still preserving the backfaces, so the number of final vertices will not be doubled. The faces will be doubled, tho - but that's the way it works: one polygon for front, another for back.

 

Always turn OFF 'show backfaces' in A:M to model for games. This way you can check how your real 'backfaces' are working. Otherwise you'll see weird overlapping patches.

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"It's better that you UV-MAP (decal) the patches before duplicating. This way you'll get both the front and back patches textured correctly. And most .x importing apps (fragmotion, 3dgs...) will be able to weld the duplicate CPs (vertex) into one, still preserving the backfaces, so the number of final vertices will not be doubled. The faces will be doubled, tho - but that's the way it works: one polygon for front, another for back."

 

I'm using the AMTEX util to export to X file. And there are no settings to use to weld the CP's is this something that will occur automatically if the CP's are close enough to each other?

Or even in the exact same spot as the original CP's?

 

When you mentioned importing, Im a bit concerned, as we have a modified X file viewer based on the AMtex viewer, but it is a custom build, and inside our game the engine is a custom build, do I need to get my programmer to make changes to accomidate welding the CP's?

 

 

Thank you for your input this has already helped imensely. :)

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"It's better that you UV-MAP (decal) the patches before duplicating. This way you'll get both the front and back patches textured correctly. And most .x importing apps (fragmotion, 3dgs...) will be able to weld the duplicate CPs (vertex) into one, still preserving the backfaces, so the number of final vertices will not be doubled. The faces will be doubled, tho - but that's the way it works: one polygon for front, another for back."

 

I'm using the AMTEX util to export to X file. And there are no settings to use to weld the CP's is this something that will occur automatically if the CP's are close enough to each other?

Or even in the exact same spot as the original CP's?

 

When you mentioned importing, Im a bit concerned, as we have a modified X file viewer based on the AMtex viewer, but it is a custom build, and inside our game the engine is a custom build, do I need to get my programmer to make changes to accomidate welding the CP's?

 

 

Thank you for your input this has already helped imensely. :)

 

 

Well, I'm no expert in .X format details, but I talk about my experience. I use AMXtex to export .X models, and import them into MED (Model editorm, from the 3DGS engine), or in Fragmotion, which is a multi purpose model editor and converter, from www.fragmosoft.com

 

I can only tell you the following tips:

 

1) Fragmotion has a Weld All command, that will weld Vertices that share same positions into one

-

2) Exporting models with AMXtex, if not checking Ignore Duplicate Normals, often will lead to fragmented models (polys that are separated from their neighbors. ) You can fix it with Weld All, but you can prevent it by always checking Ignore Duplicate Normals. Also, you could export models without exporting normals at all - this sometimes gives me better results.

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