Transparency, Reflection, Image Plane, Render Tag DEBUG

#1
Transparency, Reflection, Image Plane, Render Tag DEBUG

Here we go again with something that I've fumbled with 100 times.

I'm using Falcon renderer in this scene with Cheetah 3D v7.3b4.
I've tested with cheetah renderer too and its not correct either.

I'm including a simplified version of my scene. For my compositing purposes, the wooden bowling alley should have reflections of the bowling pins and the tree on a plane.

I've used Render tags to turn off 'Visible in Camera'.

The tree's plane doesn't allow the bowling pins' reflection to pass through onto the area of the floor closer than the tree plane. See #1

If the tree's plane doesn't have a render tag, then the bowing pins' reflection still won't pass though onto the are of the floor closer than the tree plane AND the pins become visible in the tree plane. See #2

I've tried everything I can think of - hopefully someone here can show me the mistake.

Thanks in advance!
--Shift Studio.

download file >> https://www.dropbox.com/s/tkcc1geco6m2xd5/Reflection,TransparencyProblem.zip?dl=0
 

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#3
From a first quick look: if you can live without caustics it seems to work as expected.

Cheers
Frank
hmm. I turned off 'reflective caustics' in the render properties. It made no difference.

Do you mean 'receive caustics' in the Render tag? - If yes, on which object?
Thanks very much.
--shift studio.
 
#4
Hi Shift,

I rotated the tree plane by 90/51/90 and material tag UV rotation -40°.
Now the plane is not intersecting the board anymore.

Another possibility is to rotate the tree plane upright by 90° till it is parallel to the board. Then the tree would look perspectively distorted, put you could then distort the plane including the image to counter that (maybe in PS).

See screenshot with render of the first proposal. All render tags disabled and background color in tree image node made transparent (opacity=0).
 

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#6
Hi Shift,

I rotated the tree plane by 90/51/90 and material tag UV rotation -40°.
Now the plane is not intersecting the board anymore.

Another possibility is to rotate the tree plane upright by 90° till it is parallel to the board. Then the tree would look perspectively distorted, put you could then distort the plane including the image to counter that (maybe in PS).

See screenshot with render of the first proposal. All render tags disabled and background color in tree image node made transparent (opacity=0).
Thanks misoversaturated. Its a good method as a work-around. I'm looking for a non-work-around method if I can get one as there are 360 trees in the scene, and other objects too.
I also have the option of replacing specific trees with the real mesh tree - the one I used to create the billboard image.

@Frank - can I see a render that you did? I'm not getting same results.

Thanks, Shift Studio.

edit - @Frank I see you did post one. let me review it.
 
#8
there are 360 trees in the scene, and other objects too.
I also have the option of replacing specific trees with the real mesh tree - the one I used to create the billboard image.
Oh I see :smile:

I'd recommend to use the real thing - no problem with a particle system.
Alpha transparency creates all kinds of problems because it is never really disregarded as it should be - your example here being one in case.
 
#9
Oh I see :smile:

I'd recommend to use the real thing - no problem with a particle system.
Alpha transparency creates all kinds of problems because it is never really disregarded as it should be - your example here being one in case.
I did do some testing and the billboard approach was faster in render (I think by about 2/3) but I didn't keep track of the numbers specifically.
Does that sound right to you?

As a compromise I may have two particle systems, up front, real mesh trees, in the background, the billboard setup

Thanks for you insights!
--shift studio.
 
#10
You might try Cheetah render on the scene with mesh tree instances - renders faster than Falcon and irradiance noise produced by radiosity should not be an issue on the foliage and a board with wood texture.
But with Cheetah everything depends on individual scene conditions, hard to give any general advice there.
 
#12
You might try Cheetah render on the scene with mesh tree instances - renders faster than Falcon and irradiance noise produced by radiosity should not be an issue on the foliage and a board with wood texture.
But with Cheetah everything depends on individual scene conditions, hard to give any general advice there.
Thanks Miso - Yes, there are so many factors that contribute to the render quality and render time. I just bit the bullet and waited. This project is nearly approved, and with any luck I won't be doing any more renders with it ;)

--shift studio.
 
#13
Ok - this seems to work here - even with a white "Material":

Cheers
Frank

PS: I wonder why no textures are proper connected except the image tree?
thanks Frank!

I know I renamed at least one of the texture files to be more clear, and manually moved them to a folder for the .zip - should have re-connected it.

I see your render has 'visible in reflections' turned off on the tree plane's render tag. I also discovered that turning off reflections seems to get what I need - but - upon further inspection I saw that the that there are no flowers or detail on the tree 'reflection' we see in the wood. I guess its not really a reflection in this case if 'visible in reflections' is turned off. So thats unexpected. What is it that appears to be a reflection but isn't?

Please see the new gif to see what I mean.
I'm linking a new file with the tree plane moved down.
https://www.dropbox.com/s/tq9z06uun82mgte/Reflection,TransparencyProblem2.zip?dl=0
Thats what I used to make the .gif below.

Thanks for looking into it. If anyone knows whats going on I'd like to hear it.
I don't really need any work-arounds as the project is finished and approved (using work-arounds).

--shift studio.
 

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