Blackmagic Forum

Hello, new here.

I've found myself stumped by something that might be very simple.. or not..

how does one go about masking multiple areas of a single image? The tool will not allow me to add more than one polygon mask area per polygon tool, and I haven't been able to merge multiple polygon mask tools together as desired, only one will be active at a time.. surely there must be a way - for example in what I was trying to do now I wanted to cut out multiple doors and windows from an image of a building.

While I could simply line up multiple image planes to share the projection, that seems far from an ideal solution (and not practical for other situations where the mask areas aren't linear).
Any help?

Thanks!

Hi Donald,

I'm not sure what you mean by only 'one being active' at a time?

Are you referring to the splines themselves? if so, you can group select all the mask nodes and all the splines will become active in the view.

If that's not it, please elaborate or provide a simple step by step of what you 'want' done, not what your doing to get there. It will be easier for me to guide you down the right path that way.

Good Luck

Hi,
what You probably want is to connect one mask to another - have a flow of mask and connect it to the footage. In each "next" mask node You will have "merge" option - add, merge, substract etc..
What is notable - default MERGE op does an add operation when Level=1, but SUBSTRACT when Level=0

If You're in the need of Mask merge (to connect different mask flows) - You could use merge node or a bitmap mask node

hope it helps

Hello and thank you both for your replies.

Marek hit the nail on the head - I had not tried to play with the Paint Mode options that appear once one mask is connected to another, and that was just what was needed - in the case i was experimenting with setting it to subtract successfully got both masks to block off their respective areas as desired.

Thanks again,
Donald

I stumbled on this today. In DF4, your merge had a 'mask' tab where you would organize multiple polys etc and their mode. As Marek says, now you set your first poly mask, which does not have a mode, then add additional polys etc, these subsequent shapes do have modes, so you can add / merge / subtract. Instead of being in a 'mask' tab, all the shapes are linked to the mask input of your merge node. I adopt the method of creating groups for them as Rony suggested so the collapsed group gives a cleaner look to the flow.

yeah,
groups are good, however You're stuck, if You would like to have a part of a group (i.e. a left hand out of whole character roto group) used in different part of a flow..

also this may be of help:
viewtopic.php?f=22&t=30185