Displacement map general questiion

[cneville]

Hi All,
Asssuming the displacement or bump map you are using is for a large surface, what are the advantages or disadvantages of using a large map as opposed to a smaller one?

If you tile a cloud map multiple times in PhotoShop and therefore need fewer repeats in Vray is that better, worse (or the same) as using more repeats with a smaller version of the same map with no or fewer tiles?

Any thoughts

chuck

[Visa]

Re: Displacement map general questiion

When texturing seawater (I assume that's the case, judging from your other post) I use a displacement map with rather large coverage and modest 1024x1024 resolution. That gives you a lighter displacement mesh with fewer tiling artifacts. Then I use the same map in smaller coverage in bump that gives some variation in the surface, further reducing visible tiling. Both maps are rotated at some arbitrary angle to the camera and each other.

As for pre-tiling in Photoshop, I think it would only increase the texture size and consume more memory. V-Ray can handle the tiling part if you provide it with a good tileable texture map.

And here's that mapping in visual:


And an example render:

[Micha_cg]

Re: Displacement map general questiion

Simple and great - thank you for sharing it.

[cneville]

Re: Displacement map general questiion

Hi,
Thanks for your reply. I have not yet tried the technique you suggested but will. If I am understanding your post you have basically 3 surface areas in the image. You have the smaller displacement map area, the larger bump map area and (I presume) a still larger surface disk that goes all the way out to the horizon.

The bump and displacement maps are using the same cloud map. Are the settings for the displacement and bump maps generally the same? Also are the other sittings for all three surfaces, including reflection, defuse, etc. the same?

Thanks again,
chuck

[Visa]

Re: Displacement map general questiion

Those two rectangles are actually the mapping widgets for my sea surface (it has two mapping channels), not separate surfaces. The smaller is the bump map and the larger one is the displacement. The multipliers for displacement and bump have roughly the same proportions as their mapping sizes, but the absolute values are obtained through trial and error. The material is very dark blue with fresnel reflections (IOR 1.33)

In a nutshell:
- 1 big surface (I have the radius ~900m)
- 1 material
- 2 mapping channels:
- ch1: Displacement map (large)
- ch2: Bump map (small)

Mapping controls are found in the properties panel:


ps. Sorry for the large images, I should really buy a headset and start making video tutorials ;D)

[cneville]

Re: Displacement map general questiion

Hi,
I haven't done done much with multiple channels yet, but it looks like a good time to try.

I appreciate your input and time spent.

chuck

[Visa]

Re: Displacement map general questiion

Yeah, you don't need multiple mapping channels very often. In fact, this is the only situation that I've had that needs multi channeling.
Just remember to assign the correct channels for the maps in the material editor too

Helping others is a time well spent, methinks