Negative displacement?

[thomthom]

1.
I made a displacementmap for corrugated metal sheets. Got it working. However, I'd like the displacement map to go inwards, not outwards?

I tried putting in a negative multiplier, but that only seemed to make it flat with some weird shadings.

(As I type this I got an idea; maybe I can just reverse the faces..? some double sided material..)


2.
From the manual I thought that if the global Displacement setting, Amount, was set to 1, then the displacement map Multiplier value related to model units. But it's not.

The Amount value may possibly be the most important value within the rollout, as this value will determine the scale of all displacement. The Amount value is the number of scene units of an object with the texture multiplier set to 1. This means that one could adjust the affect of displacement through either the Amount value or the texture multiplier, but because the Amount value affects all displacement, it is recommended that it be left constant and the texture multiplier be used to adjust the displacement of an individual material.

I suppose I'm interpreting this incorrect..?

[dalomar_cg]

Re: Negative displacement?

1. Flipping the faces should take care of it.

2. I'm not 100% sure how SU handles units, but I'm not sure how else the displacement would be determined. Keep in mind that the amount will be to any white parts of the image, if the image only goes to 50% gray then the height of the displacement will only be 50% of the amount.

[thomthom]

Re: Negative displacement?

I'm working with models in mm. At the moment I have a displacementmap with a multiplier of 2, which makes the white displace about 50mm. (I got a 50mm object next which I use for comparison.) So I can't seem to make any sense of the numbers.


(p.s. Inverting the faces did the trick for question #1. )

[dalomar_cg]

Re: Negative displacement?

Then I'm stumped. It follows those lines with Rhino and Max, so I'm not sure why it would be different with SU. I guess it is though. My only possible explanation is that internally, SU is using a different unit for storing whatever data it is. Then converting that unit into mm. But that seams odd to do things that way...SU does other odd things though, so???

[thomthom]

Re: Negative displacement?

Would it be of any use if I uploaded a sample file?

I gather that this question hasn't been brought up before. So either it's me that's made a mess of it, or it's some issue with SU and V-Ray?