Displacement mapping for games

leslievdb

Hey guys

i`m trying to get familiar with heightmaps for realtime purposes (mainly for characters)
Now i was wondering if anyone could shed some light on how tesselation is being used in upcoming games.

the main question i have is , how much should i rely on my displacement map to do the silhouette building . Should i keep it lower and let the tesselation do it`s work or should i have more supporting geometry?

Small example of a displacementmap rendered in 3ds max and displaced with marmoset



this would be a 30 cm / 12 inch object on a character, would this be a good thing to do or bad?

.Wiki

Looks like the right picture not uses the displacement map for tesselation. It looks like parralax occlusion mapping. Does marmoset support tesselated objects?

imperator_dk

You would need very heavy tessellation for those sphere to start looking good, i guess you need to know first whether that much tessellation is ever going to happen in a real ingame scenario.

shaderfx

As for the "amount of tessellation to make the spheres look good" it is true that you would need to tessellate quite a bit.

It would help if you already modeled very low poly sphere in the low poly object. That would reduce the tessellation amount.

Other techniques, like tessellation only on the silhouette of the object can also reduce the amount of tessellation needed.

leslievdb

Thanks for the comments guys

So basically from what i`ve heard so far is not to rely on tesselation too much and just work as if you`d be making a non displacement mapped/tessellated gamecharacter and use the displacement to add a little extra silhouette but not to make it do too much tesselation intensive silhouette building.

shaderfx

I think in the case of your object, that is correct.

However, that is not advice that applies to all situations.

For example, if you wish to create one "lowpoly base mesh" for facial animation and wish to use tessellation and displacement to make the same mesh look male or female (and any variety of looks).

In those cases, you would make the base mesh as low poly as you can to have good facial animation, and let tessellation and displacement do the rest.

That way, you can share the same face rig between the different characters while having a fairly lowpoly rig to animate with.


So in general take it case by case.

Another good tip is not to much really large polygons with really small once. You would need to tessellate a lot to get the large polygon to have enough subdivision for displacement to look good, but you small polygons would be tessellated extremely much.