Author Topic: Wrong caustic and rendertime  (Read 4207 times)

2021-08-03, 05:38:13

Suppybird

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Hi, I get very annoying issue. This is 4 test with a simple scene that include a sphere light under water surface:
1.   Plane water with default normal geometry: Bad scatter refraction, very bad caustic
2.   Plane water with reverse normal geometry : Bad scatter refaction, good caustic
3.   Cube water with reverse normal geometry : Good scatter refaction, very bad caustic
4.   Cube water + plane water ( plane water is unseen from camera ) : Good scatter refraction, good caustic, but very very bad rendertime.
Please FIX THIS for it to work good good with all the type of geometry, not only reverse normal. Thanks.

Also, Please think about convenience of user instead rigidly physical things. Example in 3delight renderer, I don't to create a cube with many mesh to render volume refraction of Water, just need a plane. Or seperate raydepth of each object or each material.

Link project: https://drive.google.com/file/d/1jskZnBDzGrg7HUa6vj1DqPzC7aSgSgL8/view?usp=sharing


« Last Edit: 2021-08-03, 10:13:56 by Suppybird »

2021-08-03, 10:13:06
Reply #1

Suppybird

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Sorry, I did type wrong word " reflection ", it should " refraction ". I re-write it. Please help me to fix this issue. Thanks.

2021-08-03, 11:37:11
Reply #2

Beanzvision

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Hi, What exactly are you trying to do? Is your scene ready to render? I can just open it and press render to see the results? Are any steps needed? When I do open it I see a few issues. I see a standard C4D camera and no Corona camera tag, there are two sets of water visible, is one meant to be hidden? Your light material is at an intensity of 1000! Which is x999 times too strong ;) It's possible to raise it but that is unnecessary, try increasing the camera's exposure instead or replace it with a Corona sphere light instead. Is the scene and settings to scale? What exactly are these render times and how are they bad? Can you please provide some results for that? 
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2021-08-03, 17:10:41
Reply #3

Suppybird

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I just want to create right caustic with any kind of water and anykind of lights ( not only simple sun ). As u can see, with a plane water, it create bad shape caustic, a have to reverse normal to have right look. And with single cube water, it completely cannot create right shape of caustic. This is not issue of camera. But thanks for the explosure tip.


 I can just open it and press render to see the results -> just do whatever you want as long as u can create right shape of caustic, not matte water is a plane, or a volume object ( like cube, sphere ), no matte it's default normal surface or reverse normal surface.

You can see skot 2 ? THat's render with a reverse normal surface of a plane. And caustic is very fast to render.
And in skot 3 ?  THat's render with a cube, caustic is wronq and very slow to render. Ie mean it must have an issue in there.

Another question, does rendertime is really different when I use a sphere geometry mesh light instead a Corona sphere light ?
« Last Edit: 2021-08-04, 04:38:47 by Suppybird »

2021-08-03, 17:14:57
Reply #4

Suppybird

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I just want to create right caustic with any kind of water and anykind of lights ( not only simple sun ). As u can see, with a plane water, it create bad shape caustic, a have to reverse normal to have right look. And with single cube water, it completely cannot create right shape of caustic. This is not issue of camera. But thanks for the explosure tip.


 I can just open it and press render to see the results -> just do whatever you want as long as u can create right shape of caustic, not matte water is a plane, or a volume object ( like cube, sphere ), no matte it's default normal surface or reverse normal surface.


Another question, does rendertime is really different when I use a sphere geometry mesh light instead a Corona sphere light ?

Please help. Thanks.
« Last Edit: 2021-08-03, 17:26:03 by Suppybird »

2021-08-03, 21:07:04
Reply #5

Cinemike

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Remember that the normals of the water surface determine WHERE above surface and WHERE sub surface are. You have a light under the plane with the transparent material. If the normals of the plane point towards this light, then renderwise seen, the water continues topwards and the light is not IN the water but just under it.

I hope this was not even more confusing ^^

2021-08-04, 00:22:30
Reply #6

Suppybird

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Remember that the normals of the water surface determine WHERE above surface and WHERE sub surface are. You have a light under the plane with the transparent material. If the normals of the plane point towards this light, then renderwise seen, the water continues topwards and the light is not IN the water but just under it.

I hope this was not even more confusing ^^


The problem is, in real life, caustic is alway created no matte your light sourse is from air or underwater.
Plus, as u can see, caustic from a cube water get wrong and take very long time to render compare to a plane water. So that means caustic currently works wrong with sphere light + volume water.

2021-08-04, 09:06:00
Reply #7

Suppybird

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Please help or at least tell me is that a bug or not for me to wait at peace

2021-08-04, 12:08:24
Reply #8

mmarcotic

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This will require further investigation to determine whether it is a bug or intended way of doing things.

Thanks,
Jan
Learn how to report bugs for Corona in C4D here.

2021-08-04, 14:47:29
Reply #9

burnin

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Simply put, scene is bad.
Attached are few 'good' results.
My advice - spend some time learning CGI basics.
« Last Edit: 2021-08-04, 14:52:38 by burnin »

2021-08-04, 16:37:38
Reply #10

Suppybird

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Simply put, scene is bad.
Attached are few 'good' results.
My advice - spend some time learning CGI basics.

Then My advice for you is Please learn more CGI advance to understand what I said. Your render reusult is useless for the problem I get ! You even don't understand basicly what I mean.
Plus, I always tend to create horrible scene in test and perfect scene in real work. Why ? Because a good renderer is a renderer can handle all the shots even that's hard shots, horrible shots or simple shot.
Thanks for trying.
« Last Edit: 2021-08-05, 04:11:30 by Suppybird »

2021-08-04, 16:39:02
Reply #11

Suppybird

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This will require further investigation to determine whether it is a bug or intended way of doing things.

Thanks,
Jan

Thanks so much, Jan <3 <3 <3

2021-08-31, 11:32:57
Reply #12

mmarcotic

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Hello,

I don't think any of the issues you've outlined are to be considered bugs, these are the products of our implementation of caustics. It would be very hard (or likely impossible) to create a solution that would create perfect outcomes regardless of user input.

Thanks,
Jan
Learn how to report bugs for Corona in C4D here.