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short223
04-05-2012, 11:12 AM
I am not a node expert by any means. I have a Normal Map node which successfully applies the normal map to my surface node (via the Normal channel), but I need to have that map (node) with an alpha map to block its effect on certain areas (just like we do in the surface layers).

I couldn't see a way to do this but as I said, not a node expert. Any help would be great!
Thanks!

RebelHill
04-05-2012, 11:38 AM
plug your alpha into the amplitude input of the normal map node itself.

short223
04-05-2012, 11:46 AM
I assume I am to use an Image Node for my alpha? Sorry to sound stupid, do I use the Alpha channel to plug into the Amplitude?
Thanks for your help!

short223
04-05-2012, 01:06 PM
Still haven't been able to get it to work. If I plug a 2D Image node of my alpha map, I used all 4 selections (color, alpha, luma and bump) but they just eliminated the normal map effect. I have the normal map amplitude at 300% but when I plug the other node it deactivates this......

Help anyone?

Sensei
04-05-2012, 04:49 PM
Add Constant > Scalar, plug to NormalMap Amplitude, try values 0.0 and 1.0.
If 1.0 is used, then normal is read from image,
if 0.0 is used, normal is regular normal of surface.

Show your node setup screen-shot. This might help helping you.

short223
04-06-2012, 05:56 AM
Hmmm.... Seems like I'm not explaining it right.

In the two attachments I have an example on how it is done with layers (just using the bump channel for examp). You have your bump texture with an alpha mask on top which will block certain areas from being affected (as everyone knows this).

I'm just trying to do the same thing with a Normal Map Node as I have a surface that I want the normal map to affect (which it does very well) but I need areas to be masked where it will not be affected by using an alpha image (just like the layers method).

In the Node attachment, you will see the normal map node and its settings. The highlighted area is the Amplitude which needs to be at 300%. The previous posters say to plug into the Amplitude channel of the Normal Node, but that deactivates the Amplitude and I loose the effect.

So, again, is there a way to apply an alpha mask to a normal map node and without deactivating the 300% Amplitude I have set?

RebelHill
04-06-2012, 06:42 AM
Yes... plug into the amplitude channel... that is correct.

I recommend you take a step back and think logically through your nodes, its the best way, also have a good read of the first part of the manual about nodes which explains the data types.

For instance, you say u tried connecting the BUMP output of the alpha image to the amp input... but think about it... WHY would u do that?? Bump is a vector quantity, but the amp input is a scalar (a number)... obv the 2 dont go together.

White (in an image) translates into 1 numerically, black =0 and shades of grey fall between.

The LUMA output of the image node is therefore what you want... because it describes how BRIGHT a given pixel/area is... delivering that as a 0-1 value (remember also that 1=100%... two ways of saying the same thing).

So if Ur wanting to go between 0-300%... or make your alpha represent that range (0-3), then u need to take the luma, into a scalar multiplier as A, and multiply by 3 (B), and plug that result into the amp input.

Make sure... ofc, that your alpha image in its node is mapped to the same co-ords/UV/whatever as your normal map has been... otherwise the 2 arent lined up with one another

short223
04-06-2012, 06:55 AM
Like I said, I haven't learned nodes as one should (didn't know Bump was considered vector and never really understood the term "scalar" until yesterday, and that the two wouldn't go together.

Your explanation however was understandable and it has worked!
Thank you for your help!



Yes... plug into the amplitude channel... that is correct.

I recommend you take a step back and think logically through your nodes, its the best way, also have a good read of the first part of the manual about nodes which explains the data types.

For instance, you say u tried connecting the BUMP output of the alpha image to the amp input... but think about it... WHY would u do that?? Bump is a vector quantity, but the amp input is a scalar (a number)... obv the 2 dont go together.

White (in an image) translates into 1 numerically, black =0 and shades of grey fall between.

The LUMA output of the image node is therefore what you want... because it describes how BRIGHT a given pixel/area is... delivering that as a 0-1 value (remember also that 1=100%... two ways of saying the same thing).

So if Ur wanting to go between 0-300%... or make your alpha represent that range (0-3), then u need to take the luma, into a scalar multiplier as A, and multiply by 3 (B), and plug that result into the amp input.

Make sure... ofc, that your alpha image in its node is mapped to the same co-ords/UV/whatever as your normal map has been... otherwise the 2 arent lined up with one another

RebelHill
04-06-2012, 07:05 AM
Nodes are basically just a logic process... honestly, familiarise yourself with the data types, there's only 5 (or 6, is it 6?) and then a lot more will start falling into place, promise.

Glad u got it sorted though.