make specific trees semi-transparent

[Konichowaa]

Hi,
I'm working on a project where I would like to make some specific trees semi-transparent to show what's behind them.
I tried making the materials transparent, but with 3D trees, when too many leaves behind each other, the effect of transparency is lost (in the centre, on the edges the effect is as expected)

So, I was thinking I might need multipass (mask the objects?) and compositing, but (a bit shamed to admit ) I have never used multipass before so very newbie about that...

Can somebody explain me, what the best way is,  to do this, by detailed step or example file?

many thanks!

[Beanzvision]

Hi, have you tried lowering the opacity strength of the material? Seems to work well here ;)

[BigAl3D]

Are you rendering a still image? That would make this much easier, but could also work with animation. Would also help to see your shot. The issue I see with Multi-Pass, is that you want to show the objects behind the trees. Multi-Pass can generate masks for the trees yes, BUT you will not have the full background object visible where the trees are.

If it's a handful of trees, you could use the Corona Compositing Tag on the group of trees that you want transparent and another tag for the rest of the objects. I would use C4D's Take System. Hopefully you are familiar with Takes. So powerful, but you need to know a few things.

Take 1:  The first take has the compositing tag for the trees "Seen by Camera" set to OFF. Compositing tag for all other objects is set to ON (seen by camera)

Take 2:  The opposite of the first. Trees ON and other objects OFF

Each Take can have its own render settings so each Take can save images with different names. Choose PNG or PSD with transparency and composite away. Now your GROUP of trees, no matter how thick, can be made as transparent as you need since it's one layer.

Let me know if you have any questions as this can get confusing when new to this concept.


@beanzvision Konichowaa addressed this saying that once you have several trees with transparency, the effect lessens and gets weird. I haven't tested this, but it make sense to me.