Let me introduce myself. My name is Kevin "Q" Quattro. I've been working in vfx since 1996. It's been a heck of a ride. I did a stint at Digital Domain way back in 2002. I recall a very early version of Terragen back then. It's come a long way.
We've been using Vue for quite some time here. Vue has been mostly terrible for support and the program itself rather cumbersome. Still, we managed. However, their cloud system really has stagnated. This is what had me think to look up Terragen once again. All I can say is wow! Looks fantastic!
I already have the shop very close to switching over. The clouds, terrain, and atmosphere look stunning. I have been running in to one issue with the water (lakes) that I am having difficulty over-coming. I have watched many of the YouTube videos to get up to speed (the basics) and read through many posts here. I am at a loss for what is causing this issue. The issue? Little black spots scattered over the water. I've attached an example. For simplicity I've turned everything else off and set AA to "1."
Any ideas? Thank you for your time.
Welcome to the forum and Terragen world. Are you using Path Tracing?...I don't have that version yet, but it's been said it doesn't play well with water yet,
Welcome to the forum.
It would be faster if you could post the basic TGD file with the problem here.
Hi Kevin, and welcome to the forum!
I think this might be solvable with certain combinations of settings in the Render Subdiv Settings: https://planetside.co.uk/wiki/index.php?title=Render_Subdiv_Settings
Subdiv Settings are accessed from the Advanced tab on the render node.
However, I'm surprised to see a scene that shows such a large number of these black spots. The advanced settings should only be needed in rare cases. Would you send us your scene, or something that replicates the issue for us? You can email support@planetside.co.uk if you prefer not to share it here.
I have made a scene in an attempt to reproduce the black artefacts that sometimes occur on Water Surfaces in Terragen, it seems to occur when the Water shader settings are changed from the defaults.
The steps I followed to create the scene were as follows:
Create a new scene.
Add a Lake.
Increase the Lake > Water Level from 1m (the default) to 20m.
Change the Render Camera position.y from 10m to 30m, otherwise it is underwater.
Increase the Water shader > Roughness from 0.02 (the default) to 0.04.
Increase the Water shader > Wave Scale from 10 (the default) to 80.
The Water shader > Seed Seed setting in my scene is 38250.
The artefacts are visible in both the 3D view and the render at the default settings.
I have rendered out the scene with Render node Render 02 with changed settings:
Micropoly detail: 0.8
AA: 6
[attachimg=2]
I don't know which Render node settings to change to eliminate these artefacts.
I'm not sure why, but increasing the Micro-Poly Detail to 2 seems to get rid of the black spots. That's double what I normally use though. I have never had to go above 1 before.
[attachimg=1]
-Derek
Thank you for all the replies! I have attached the TGD file. It looks from one of the replies I see where I may have triggered this issue. I did mess with the default water settings quite a bit. This scene is not using Path Tracing, to answer another question.
Thank you all again!
On the Water shader, what does the parameter "Displacement Tolerance" on the Surface Shaders Tab do?
The documentation is a bit lacking ;)
https://planetside.co.uk/wiki/index.php?title=Lake_-_Surface_Shaders_Tab (https://planetside.co.uk/wiki/index.php?title=Lake_-_Surface_Shaders_Tab)
Displacement Tolerance is the same for all object nodes, so we just need to copy the explanation to each of them. Here is the info on the general Displacement page:
http://planetside.co.uk/wiki/index.php?title=Displacement
"You might find surfaces with rough or spikey displacement occasionally show problems, such as being cut off at bucket edges or causing gaps in ray traced shadows. Some nodes, such as the Planet, have "Displacement tolerance" parameters which can help to improve this. Changing this parameter can greatly increase render times so you should only change it if you have a specific need. The default value is 1. If you're having problems try increasing it to 2. If that improves things but doesn't completely resolve them then try increasing it by small increments. You would not generally want to go above a value of 4 or 5 however."
- Oshyan
Penboack seems to have reproduced my issue almost exactly. The tolerance settings sounds a lot like the Ray Epsilon setting in Octane. Good to know.
Displacement Tolerance should generally only be necessary when extreme displacement values cause a piece of displacement to cross tile boundaries, or otherwise be cut off. I don't think that's the cause of these black spots.
- Oshyan
Does Micropoly detail have any effect on water? Or just the terrain under it? Just curious as to why it seemed to reduce the black spots.
-Derek
Unless Defer All or Ray Trace Everything is enabled, then the micropoly does indeed affect the water. When Path Tracing is enabled, Defer All is forced-on.
- Oshyan
Micropoly detail affects the water in all render modes, including Defer All and Path Tracing.
I stand corrected, and I learn something new almost every day. :D I suppose I should have known this actually, knowing how RTE works re: micropoly detail, e.g. for terrain.
- Oshyan
Quote from: D.A. Bentley on March 24, 2019, 05:19:46 PM
I'm not sure why, but increasing the Micro-Poly Detail to 2 seems to get rid of the black spots. That's double what I normally use though. I have never had to go above 1 before.
[attachimg=1]
-Derek
I tried this on the pixelsmack scene, it did not eliminate the black spots, although it did reduce them.
It did increase the render time from 00:30:14 to 01:48:01!
You can get rid of some of the worst holes by turning "Fully adaptive" OFF in Advanced -> Subdiv Settings. It might be possible to remove the remaining ones by turning off Microvertex Jittering, but that can sometimes make geometric patterns more visible in the water.
Perhaps a reflective shader with slightly smoothed (0.004) reflection may help (instead of the water reflection), I don't know actually.
Thanks Matt, Dune,
On my test scene turning "Fully adaptive" OFF in Advanced -> Subdiv Settings eliminated the black sports.
Using a Reflective shader for the reflections eliminated most but not all the black spots, but it lacks the Horizon shift parameter which I think might be useful for ocean surfaces.