Cineversity

Hi from Sharon in Texas!
I was looking at different ways to mask objects using redshift.

One way is to add a cube, and then another primitive (plane or cube), the masking object,  and put a redshift tag on it, and set it to Matte> Enable, show background. That seems to work to sharply block the cube.

Someone else had suggested putting a transparency on the masking object, then placing a redshift tag on the cube, and set it the visibilty Override to ON, and uncheck “visible in refractions”. I could not get this to work, even if i put the tag on the blocking primitive.

But, want i really wanted to do, is use an object to fade out another object, so i can animate it, using redshift.
I tried using a gradient in the opacity of the masking object, but that didnt work.

Of course, i may be going about this the wrong way.

Any ideas?  I didn’t want to use polyfx, bec i dont want to shrink each poly.  i just want to make them invisible gradually.

thanks!
Sharon Palkowetz

Hi Sharon Palkowetz,

Any ideas? Sure

One way to do it is to render one pass with and without. Then blend this over time, e.g., After Effects, between the two.

Using an object to “hide” an object is not really an option, as the hidden object will contribute to GI and shadows, reflections, and other things. This is, of course, scene-dependent.

With the two-pass blend, all these problems vanish, and an adjustment is made quickly, like “we need that blend faster”, “slower”, etc.

How it vanishes can be even art directed, as all you need is a black a white animation as matte/alpha in Ae.

Would that work? As I don’t know your project, there might be things that would prevent this.

All the best

Hey Dr. S
Thanks for the speedy reply. yeah that makes sense.

However, is there a way to just fade out an objects opacity in redshift, ie. animating the fade out or fade in?
We used to be able to use a display tag and we could fade out the transparency that way, but if course, that won’t work with redshift.

Thanks!
Sharon

Hi Sharon,

How about Material> Overall> Opacity? I assume that leaves unwanted reflections and such.

To my knowledge, the RS Object> Matte is a full or nothing when a gradient (Ramp) is applied to the object itself.

I have already suggested solving it in “post”, so I will not point to similar ways, even though I think that is the way to go.

If the background image is fixed, “frontal projection”, I would like to suggest this option:
https://www.dropbox.com/s/8nx5m0t9qt61bgm/CV3_S26_drs_22_RSro_02.c4d.zip?dl=0

I used a radiance image for the background just for the demo scene; not my suggestion at all to use them in production.

Have a great weekend

hey Dr. S
Thanks for getting back to me again.
Allright! I just wanted to make sure i wasn’t missing something. Maybe this could be a feature suggestion.

Thing is…if i have a 3D object, and i render out the scene with the object, and the scene without the object, i can do a gradual fade out.
BUT, if i wanted to do a fade of the object from front to back, it’s hard to do that in post. 
Noseman had suggested using polyfx, for a project i was working on, and that worked ok, but if i wanted to fade an object from front to back, especially if i wanted to use a field to do it, having a way to gradually fade through zed space is really needed.

Thanks for the help!
sharon

Hi Sharon,

Your example sounds like a case for an Opacity animation for the object itself.

You need to have a piece of information that created that kind of transition; a gradient, a Vertex map growing, or anything else. That can be rendered as a pass as well. Then it can be used in Post.

Those more detailed Blends can be done with a Position Pass; for example, we talk about an object I have not seen. So the discussion of general nature and with that might not fit at all.

As usual, I can give you more precise information if I have an example scene.

Perhaps even an animated Boole might work, while I don’t know if that is possible without artifacts, again: not having anything to work with.

In VFX shots on TV or even in movies, I sometimes find it weird to see something disappearing and having nothing inside; only the surface is going away. Here I would love to see your project and hopefully find something that would work convincingly.

All the best

Hey Dr. S!

I wanted to show you a video i worked on, but it hasn’t been released yet. As soon as it’s published, i’ll show it to you and maybe you’d have some thoughts on what I’m trying to do.

In the meanwhile…

I did some testing.  So it appears that the display tag can work if you crank up the transparency samples.  I only tested it with a cube primitives, but it could work in some cases. That’s great for just doing an overall fade of an object.

However, I still haven’t found a good option for creating a transparency for moving in ZED space across an object, like a wipe, which is what i was referring to in the first part of this comment. 

So, a feature that would be really cool, is if the geniuses of Maxon could implement a gradient for transparency in the matte redshift tag. That would solve the issue!

Thanks for your help!
Sharon

Hi Sharon,

Thanks for the update.

I hesitate to suggest this cover of another object, as you have two objects in the scene that might influence others or need attention to limit that interaction.

If I can see what you like to do, perhaps new ideas will come up. There are certainly many options along the whole pipeline.

My best wishes for your project