through the surface

Started by gasbutan, November 18, 2019, 04:21:08 pm

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gasbutan

Has anyone ever tried to produce an image like this in Terragen ?
I tried different techniques using just the lake, a plane or a card, or even a cube with a glass shader for the water.

Thx

vue42_1ck.jpg

Dune

Lake, plane, card sphere would all work, I'd expect (as they could have no shadow), with a glass shader (maybe doublesided?), but you didn't succeed?

WAS

Well you actually reminded me I have a test I wanted to whenever I got ability to animate which is a displaced plane with glass shader for a underwater effect like you got going on here. I never did do anything with it. Did it a long time ago when doing a underwater scene with some fish cards.

gasbutan

Thank you, Dune for your recommendations.

Here are some test renders:

1. Lake
test016d_lake.jpg

2. Plane
test016d_plane.jpg

3. Cube (camera inside the cube)
test016d_cube.jpg


All objects have a glass shader with double sided ON.

WAS

Quote from: gasbutan on November 19, 2019, 04:32:07 pmThank you, Dune for your recommendations.

Here are some test renders:

1. Lake
test016d_lake.jpg

2. Plane
test016d_plane.jpg

3. Cube (camera inside the cube)
test016d_cube.jpg


All objects have a glass shader with double sided ON.

This is quite interesting. Plane seems to provide the best effect though is it me or is the object parts being individually displaced?

Dune

I did a little test yesterday, and found that lake doesn't work properly, but an inverted plane (or sphere) does. I also set glass shader to single-sided and an inverted decay distance. Some reeds in water, some palms on shore, which can both be seen.
I must say, I find the reflection of the trout (courtesy of Doug Campbell) rather vague (though that vagueness was better visible without all the reeds).
Path tracer nicely blurs everything above water, this is a standard render.

gasbutan

@WAS:  yes, the plane shows the strongest effect. Nevertheless it is not what I expected.

@Dune:  Wow, this really looks good. Thank you, I will try this setup.

Hannes

Quote from: Dune on November 20, 2019, 02:37:00 amI did a little test yesterday, and found that lake doesn't work properly, but an inverted plane (or sphere) does. I also set glass shader to single-sided and an inverted decay distance
Wow, that's smart! Cool, Ulco.

WAS

Quote from: Dune on November 20, 2019, 02:37:00 amI did a little test yesterday, and found that lake doesn't work properly, but an inverted plane (or sphere) does. I also set glass shader to single-sided and an inverted decay distance. Some reeds in water, some palms on shore, which can both be seen.
I must say, I find the reflection of the trout (courtesy of Doug Campbell) rather vague (though that vagueness was better visible without all the reeds).
Path tracer nicely blurs everything above water, this is a standard render.

Perhaps a secondary reflection surface without heightlights would help bring out the under-side reflections. I seem to recall you suggestion this method before with just the water surface plane to give it a better "watery look". Cool to see it in action. Pretty sure that's where I tried a plane for the camera and warping the whole scene (like underwater stuff in games).

gasbutan

It works, great!
Thanks for the assistance !

Underside reflections are an interesting challenge. It would be interesting how to manage total internal reflection effects.
The surface close to the camera should be transparent, whereas parts of the surface at a greater distance should be reflective.
I think I have to start some research.... ;D

test016e.jpg

Dune

You could use a distance mask to set further away to just reflection and close-by to transparent. That is what I often do in topdown water scenes to decrease rendertime. I don't know if the glass shader would take care of that itself. Water shader might, but I'm not sure actually.

gasbutan

Distance mask is a good idea. I will try that.
On the othe hand it doesn't only depend on the distance but on the angle between lightray and the surface, and this might change with the waves. So you will have a transition between transparency and reflection...

Matt

Proper refraction and internal reflection should work if the surface normal is facing upwards and the camera is below it. Displaceable surfaces like Plane and Lake aren't visible like this because of back-face culling (at the time of writing, v4.4), but the non-displaceable Card should work with a rotation of -90 on X. Then you don't need to fake the reflectivity, it'll be physically correct internal reflection.
Just because milk is white doesn't mean that clouds are made of milk.

WAS

Quote from: Matt on November 21, 2019, 02:23:32 pmProper refraction and internal reflection should work if the surface normal is facing upwards and the camera is below it. Displaceable surfaces like Plane and Lake aren't visible like this because of back-face culling (at the time of writing, v4.4), but the non-displaceable Card should work with a rotation of -90 on X. Then you don't need to fake the reflectivity, it'll be physically correct internal reflection.


Ohh, that means a few of my old underwater scenes should work fine. I was using just a card with water, though would need to disable the secondary card for shadows.

gasbutan

Thank you, Matt for the valuable note. I will experiment with this settings.