Why is displacement map used here instead of actual geometry?

[Playdo]

I've seen a lot of tutorials where they'll model a detailed surface and then render a displacement map from this, which will be used later for displacement. What's the benefit of using this instead of the model?

[abmitalia]

Poly -count ? render time ? surface detail enhancement ? But I think you know that. What is your precise question?

[Playdo]

But displacement adds geometry at render time, so it wouldn't differ much from actual modeled geometry. From what I've read, displacement doesn't render faster (I haven't tested)?

 

My precise question is what is the benefit of using it, like it is here:

http://www.peterguthrie.net/blog/2010/06/free-texture-expanded-metal/

[jinsley]

modeling to that detail on a large project would be a pain. especially when it comes to updates and changes from a client and dealing with complex geometry that doesn't necessarily occur on flat surfaces (organic stuff).

 

Its much easier and time efficient to update models when you make smart use of displacement maps and uvw mapping "flat" geometry.

[Playdo]

You say it's beneficial if changes need to be made later on. So if the model is not going to be altered then there is no benefit (other than polycount for viewport purposes)? You might as well leave it as geometry rather then producing displacement maps from it?

 

I'm no expert here, so I may have totally missed the point.

[jinsley]

Which is easier to manipulate?

 

a plane --> 4 vertex to manipulate if it changes sizes or needs to be copied to another location... you can keep the uvw mapping the same...

 

or modeled geometry --> thousands (millions?) of polys per panel to edit if it changes sizes for a different location and you can't scale it because then the mesh in the panel will change sizes...

 

doesn't make sense to me to have a piece of modeled mesh that detailed... UNLESS it is a few feet from the camera and then you would only need 1 or 2 maybe.

[jinsley]

sorry, meant to add...

 

what other reason do you need other than to save polycount? If you can't turn the layer off because you need to see these meshes for some reason, who has the time or the budget to sit around and wait on updating view ports all day...