bump maps vs 3d

alan bard newcomer

the attached image is a 3d model I built...  the insets in the wall are inset the window sills stick out etc
---
all the light comes from the street light below
---
if I was using a flat plane with a texture and bump maps .. would the same kind of lighting effects take place?

Richard Haseltine

You wouldn't get cast shadows.

JonnyRay

My tutorials Displaced Bumps and the follow-up Is This Normal? talk about the differences between Bump, Displacement, and Normal maps for adding details to your geometry. Basically, the only way to get shadows that cast on the plane would be to use Displacement, but for something as deep as a window well, I would say you'll need to put at least some of the detail in the object itself as the map methods are really designed for more detail level changes not something as significant as sinking the windows back from the face of the building.

Mattymanx

Its depends on what its needed for and that would determine the best course of action.  Games require lower polygon models where as 3D apps can handle much higher res models.

For 3D apps, if you need it for close ups, modeled details work best and can still have Bump, displacement and Normals added for more details on top of that.  If you need it for distance shots, a basic model with textured details may be best.

alan bard newcomer

any guess as to whether just having the model 3 dimensional putting the load on the program is better than using displacement maps and putting the load on the render engine?

 

JonnyRay

alan bard newcomer said:

any guess as to whether just having the model 3 dimensional putting the load on the program is better than using displacement maps and putting the load on the render engine?

 

As a rule, you'll hear more complaints about the time it takes to render something than how responsive the model is when you're setting up your scene. Calculations like displacement can be very costly in terms of rendering time; so you're probably better off adding polygons to the model geometry than relying on a render time calculation like displacement.

Mattymanx

Load on the system or render engine depends.  If it has lots of maps and you are rendering in Iray, then the maps will be a larger resource hog of the limited vram. 

alan bard newcomer

actually the buildings have no maps...  nothing but textures on objects... 
---
this is the full scene that the wall section up above is from ... 
it was 2700x 1000 took two hours to render with my 980ti 6g version... 
the street lights are the only light except for the  night sky ...
I wired them together so they are just one light in terms of adjusting
---
I have yet to debug why occasionally iray can't handle the light on the lamp posts...