Assign automatic from Bones and overlaying faces


I’m trying to rig those pants and assign automatic weight from bones and here is the result:

Those are the same objects, just overlaying faces
It’s basically touching only the first faces it meets and stops there

Maybe my question is stupid and its the nature of the function but I was wondering if there is a way to make it go beyond and catch the details like the belt , pockets and such? Or if there is a similar method / technique that could do it (from envelopes just surround the whole thing)

Because painting them manually in exact sync with the pants under is very tricky, I’ve been trying for 2 days…
I get pretty darn close by painting roughly before using a blur plugin but it’s just never perfect.

What would be the best way?

Thank you

For overlapping face like that, use “ With Envelop Weights”.

as I mentionned when i’m using with envelop it surrounds the whole thing way too far from the bone
here is a snapshot of it

Is there a way to have more control over that?

Envelop influence can be controlled by controlling the envelop size. Your bone display in the image is Stick. You need to change bone display to Envelop. Then you can see the bone volume it will cover. You can adjust the bone volume by changing the bone head and tail radius as well as Envelop size setting. The slider bars for those settings are located on Property panels, hot key N, in Edit mode.