displacement map issue

[sooon]

hi guys,

after a few day of research and reading, i still find myself having some questions on displacement map. how that someone you will shed some light on this topic.

ok, basically what i understood of displacement map is when you do so, they actually saved a basic model( or base in zb case) and a displacement map( that like bump map except that it actually bake to the vertices level).

first, how different of them if compare with the actual detail model(that over millions of poly) in terms of rendering time? is that a way to calculate this??

and how should we decide on the minimum polygons to use for the base object?

any other technical aspect other than render time?

or

anywhere can i find the comparison of the normal detail model and displacement map model?

thanks in advance :)

[aminuts]

Hi Soon,

This is a good thread to check out while you wait for your answers.....

using displacements in outside renderers thread (http://www.pixolator.com/zbc-bin/ultimatebb.cgi?ubb=get_topic&f=1&t=015376)

you can view Pixolator's model...high detailed, low poly, and using the displacement and see for yourself how it looks in Zbrush and in other renderers for some comparisons.

[Kanga]

Hi sooon!


first, how different of them if compare with the actual detail model(that over millions of poly) in terms of rendering time? is that a way to calculate this?? What you would be comparing I guess is the increase in render time compared to decrease in modeling time. You would only be concerned with millions of polys if you were rendering in another aplication and making an animation instead of a still as all those polys arn't an issue in z_brush.


and how should we decide on the minimum polygons to use for the base object? How you would decide on how many polys in another app would be to make a small preview and settle on a minimum or maximum quality of your output render, then a full sized view and time it.


any other technical aspect other than render time? The all important one,.... what level of detail do you need? How much time do you have left :D?

Hope this helps,
Kanga

[sooon]

thanks kanga.

well, i guess i m not experience enough to know all this before hand. and i think the best way to learn this is to try out what my doubt is, which i m still not so sure about my consent:P

i just exploring thru 3d applications and never really in the industry. i think you more or less guess it:P

[Ctrl-Z]

"How many polys" is really a question of what you're planning to do with your model. Remember, you're animating the base mesh. If your character's eyelids are suggested only by displacement map, with no underlying geometry in the base mesh to back it up? Good luck making that guy blink.

It's always better if the modeler also animates, if only in their spare time. The best way to avoid problems like I just described is to simply know better. ;)

It's a very Maya-centric book, but I still recommend Jason Osipa's "Stop Staring: Facial Modeling and Animation Done Right (http://www.amazon.com/exec/obidos/ASIN/0782141293/fallenskybooksto)" as a great place to study the mindset behind which polygons are important and why your base model had better include them.