Need to 'mask' a VRay Normal Map

[RobH2]

I had assumed that creating a Mask Node and attaching a Normal Map (Map slot) and a gradient (Mask slot) that I could mask the effect of the Normal Map in a VRay material. However, that does not work. The Normal Map gets completely wiped out. I tried using a modified Normal Map to mask itself by painting out the parts I wanted to mask with the same blue, and use that for the mask,  but that failed too.

How can I mask an area of a Normal Map?

[paulneale]

I can only suggest that you are doing something wrong as if the normal map doesn't have information in it there is no way that it could possibly be making it up just by it self. Are you sure that the material that you are working with is assigned to the node that you are rendering?

[RobH2]

Hi,

Yea, that idea to mask it with itself was a last-ditch effort. I began by doing it the way I always have by using a black and white image as the mask. That curiously didn't work so I was just stabbing in the air. I knew the "masking it with itself" was not going to work but wanted to at least let readers know what I had tired.

Still can't get it to work, hmmmm....

[paulneale]

I don't have VRay on this system but what you are doing should work. 

[RobH2]

Yes, it should but it's not. I'll keep experimeting. I have two hours into this and it's odd. I've masked a regular bitmap (photo) so I know my system is OK. The Normal Map just won't behave with a mask. I've even tried different Normal Maps to see if it was a bad Normal Map. No luck.

Thanks

[RobH2 · Accepted solution]

Reporting back in case it helps someone else. I had followed a suggestion from a post about using Normal Maps with VRay. It suggested that I create a Standard Normal Map node and attach that to the 'Bump' slot. Running into that Standard NM it said put a VRay Normal Map. I loaded my Normal Map into the VRay NM. That worked well before I decided to use a Mask.

It looked like this:   Bitmap (Normal Map)--------->VRay Normal Map-------->Standard Normal Map------->VRay Material(Bump Slot)

So, when I started thinking about using a Mask, I put a 'Mask' node between my original Normal Map and the VRay Normal Map.

That looked like this:  Bitmap (Normal Map)--------->Mask Node-------->VRay Normal Map-------->Standard Normal Map------->VRay Material(Bump Slot)

That did not work and I tried a bunch of other things. So, what I did was ignore some of the directions that I read in that post and I created this, and it worked:

Bitmap (Normal Map)--------->VRay Normal Map-------->Mask Node------->VRay Material(Bump Slot)

By dropping the Standard Bump Map node and moving the Mask Node to just before the Bump Slot, it seems to be working. And it goes to show you, be careful about how much you trust solutions or tutorials you find on the web. While helpful, some of them may not be entirely correct.