[Papervision3D] PV3d vs. Away3D - what the difference?BE SPECIFIC!

[Krobill]

Hi,

the naming argument whether nomal map is bumpmapping or the opposite, I
don't care. But it's rather short to summarize normal maps to something you
can obtain from heightmaps. Sure heightmaps can be converted to normal maps
but you can't achieve half the effects of normal maps with them : try to
find an height map that once treated will have pixel pointing at the
opposite of the polygon normal. I think you'll have a hard time to do that
and it does have its uses. 
Height maps are only useable for artists to add high frequency details on
their model and it's feasible by a human brain in photoshop. Normal maps can
also be used for low frequency details in ways that height maps won't be
able to reproduce because they lack information as stated by Peter.

Regards,

Alain
http://blog.krobill.com




Antoine Azar - 2XM Labs wrote:
> 
> Hi Peter,
>  
> We might have a difference in definitions (and I've heard different people
> use different terms), but here's my take from my years as a 3D engine
> developer:
>  
> I'm not sure what you mean by bump maps being 1 dimensional displacement
> above or below the surface. You may be referring to two things. In one
> case,
> from a grayscale (1-dim) bump map, you can easily compute a 3-dim normal
> map. You just need to compute the slopes in X and Y at each texel and do
> some cross product magic. You end up with a normal map (which you
> explained
> quite well). This is useful to save on texture memory (3x smaller) if you
> can afford the extra computations at render time, and is easier for
> artists
> to draw.
>  
> The second thing you may be referring to is displacement mapping, and is
> way
> more powerful (and costly) than other techniques. It requires
> re-tesselating
> your geometry in an adaptive way to create new vertices where needed and
> displace them. You can start off from a base model, and end up with a very
> detailed one by letting an artist simply draw his displacement map. If you
> look at the model on the side, you'll see the detail of the geometry
> (which
> you won't in normal mapping, as only the normal is modified).
>  
> To go back to the definitions, bump mapping generally refers to the whole
> family of techniques to modify a geometry based on a map. Normal mapping
> is
> one of them. Wikipedia explains this pretty well.
>  
> Cheers,
>  
> Antoine Azar
> 2XM Labs
> 645 Wellington W.
> Montreal, Quebec
> H3C 1T2, Canada
> T. 514-606-4821
> http://www.2xmlabs.com <http://www.2xmlabs.com/> 
> 
> 

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