Top coat weight LIE gradient

arthenics

Hello,

I've tried to use gradients with top coat weight but it doesn't work as expected :

- Using a jpg, top coat weight follows the gradient but "black transparency" is opaque : I can't use several LIE.

- Using a png, I can use several LIE but the gradient is gone : whitish greys turn white, blackish greys turn black. And if I use a "cheat" as creating a black layer as first layer, it will not work as a LIE if I save this black layer with each lie, it will become the same problem as it is with JPG. From what I see, PNGs with "black alpha" and "white alpha" end the same.

How to handle this? Any tips? Or it can be considered as a bug?

 

Since it's for a product "for sale", I would prefer to avoid the quick and dirty (lazy) fix as to create a "base_LIE" to add before applying the LIE using top coat weight...

felis

I don't think I can follow what you are trying to do.

arthenics

Hum...

- Top Coat Weight is a slider from 0 to 1.

- We can use LIE with top coat weight.

- I need to use a gradient with Top Coat Weight. In other words, top coat weight needs to always exclude some part BUT I need it to be a smooth transition..

- In other words it's similar to a smooth gradient between, black, white AND transparency.

- And I need it to work with different layers... 

My problem :

- If I use JPG : gradients work but the layer +2 will hide the layer +1 and 0

- If I use PNG, layers (0, +1) are not hidden by the top layer (+2) BUT the gradients are not working. They work if I change to

• layer 0 : full black
• and ex png layers move from 0 to +1, +1 to +2 and the last +2 to +3.

In other word, top coat weight detect the png gradient only if there is a black layer.

Top coat weight seems to have a conflict between png transparency and weight transparency.

From what it seems, Opaque layer + png layers are converted as an opaque layer and then weighted.

Then :

To layer png and make the gradients work, I need a way to add an opaque layer at level 0 and be sure other layers are going over.

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Currently, since LIEs and materials are not saving the same parameters, it seems that the best solution is to create a "base material" (saved as material) to add first and to create LIEs (saved as LIEs) to apply over after.

 

felis

The final result for weight can only have 0-1 (black-white) (at least I do not know how Iray would handle transparency there).

Do you want that the user shall be able to change it, else I see no reason for using LIE.

I would advice that all your layers only use greyscale.

For each layer you should combine it of a layer and a mask to give the weight of that layer.

Which blend mode are you using in LIE?

arthenics

- Yes, I wish the user to be able to customize/load what he needs

- Blend mode is source over

Even if it's not really clean in my opinion, since some parts need to be used as a predefined base, I will just create a base material with a black layer to load first. LIEs will stack over. I will just need to make some kind of easy-to-understand quick how-to. After all "Documentation" folder and content are not for show.

felis

Source over means that the uppermost layers "wins" (if it has oppacity). So if you have something lightgrey below something darker grey, it will be darker grey. That might be what you want, if you have designed it after it.

I am uncertain if you understodd how I suggested to do it, with layers and masks.

I have attached as image with an exampel. The masks controls the oppacity of the layer.