Can't a mask be transparent?

[Franky1966]

I'm having a mask and in that vectors who partialy must be invisible (a hand that disapears in a gap). The mask is not totaly transparent but a little opaque (Alpha 254) . Problem is that I otherwise can't see the hand. But it turns out in the render the hand won't show, probably because the masks alpha settings.

Question is: must a mask always be filled with a color? I can not imagine it so I'm probably missing something.

[Greenlaw]

I'm a little confused by your description: Do you want the Mask to not be visible or do you want the result of the masking to be semi-transparent?

If it's the former, you would use one of the 'Invisible' masking options. This makes the mask work on another layer but not render itself (it's invisible!) It also makes the mask invisible in the Workspace...which, I think is what you want?

If it's the latter, you can make the layer (not the mask) semi-transparent by setting the layer's Opacity level to what you want. You can also make a visible mask semi-transparent this way if you like.

If none of these is what you want, can you post a screen cap to illustrate?

[synthsin75]

Completely opaque is alpha 255, so you setting it at 254 is just a little transparent.
A mask has to have filled shapes. Vector paths alone won't do.

[Franky1966]

Oke, here's a pic.

You can see the mask with the red outline. Of course this line must not be seen in the render, but this is now for clarity. Bugs right hand dissapears behind Bugs left hand but still there's a piece of the carrot sticking out at the left side (always the carrot ) Therefor I have to mask it.
The mask has no fill. If I mask the right hand and carrot, it will not show, therefor I give the mask a fill and set the opacity to 1 (I said that wrong in the previous post, Synthsin75) so the hand will mask and it shows on screen but the mask doesn't cover the background. Unfortunately it won't show in the render. Due to it's opacity settings I guess.
For clarity; in this pic the hand isn't masked.

So I thought: is it possible to mask with a no fill vector mask?
And if not: what is a good workaround?

[Lukas]

The mask and carrot both have to be in the same group. The mask layer must be *below* the carrot layer. Like so:

• Bug Bunny Group (Mask Group: Reveal All)
  • Carrot Layer (Layer Masking: Mask this layer)
  • Mask Layer (Layer Masking: - Subtract from mask (this layer will be invisible))

The group can contain many other layers, just set those to Layer Masking: Don't Mask this layer

The mask should have a solid fully opaque fill. With the right settings it will not render. (Don't check Don't render this layer by the way, it will also stop the layer from contributing to the mask).

If you're familiar with how alpha channels work:
Imagine "Reveal all" as a white base for the alpha channel.
Imagine "Hide all" as a black base for the alpha channel.
Then from the bottom to the top (this is how Moho renders), layers will add (add white pixels) or substract (add black pixels) to the alpha channel before rendering their own pixels within the boundaries of the alpha channel (only where white pixels are), stacking pixels on top of what's already rendered.
If you keep this in mind, masking will be much easier, 'clearing' the mask will also make sense to you. (You don't need it in this case)

[Franky1966]

Thanks Lukas.
The '+ Add to mask, but keep invisible' on the mask layer (and the mask fully opaque white) did the trick.
Thanks for clearing this out. Another thing learned!

[Lukas]

Thanks Lukas.
The '+ Add to mask, but keep invisible' on the mask layer (and the mask fully opaque white) did the trick.
Thanks for clearing this out. Another thing learned!

No problem. Just to be clear, the mask's fill doesn't actually have to be white. Any color is fine. In the Alpha Channel (that you created with the masking settings) the pixels are black and white.

Like this (the image on the right is the alpha channel of the image on the left, alpha channels are only black (transparent), white (opaque) or a grey value in between (semi transparent)):

[Franky1966]

Thanks for clearing that one out too, Lukas.