Sneak Peek: Terragen 4.1 Change Log

Started by Matt, July 06, 2017, 07:14:34 am

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Oh, do we have a big update coming your way!

As I am editing the final change log, I'm struck by just how much we've packed into the next update. It will look something like this:

Terragen 4.1 - Coming Soon

The Linux render node (Professional Edition only) is now built against the VFX Reference Platform CY2017.

Fixed Bug #693: Pausing a render could cause the application to freeze.


Approx 2.2x speedup of the Voronoi functions used by by Power Fractal Shade V3, Fake Stones Shader and non-smooth Voronoi function nodes.

Approx 1.4-1.5x speedup of the smooth Voronoi functions. These are used by Power Fractal Shader V3 when filtered by a Smoothing Filter Shader and are also used by the Smooth Voronoi function nodes.

Alpine Fractal Shader V2 is now about 12% faster.


Terragen 4.1 now renders Cloud Layer V3 and Easy Cloud in a different way from 4.0. There is a new global control called "Voxel scattering quality" in GI Settings (on the GI in Clouds tab). This affects all cloud layers of type Cloud Layer V3 and Easy Cloud, and is independent of the cloud layers' individual quality parameters. The default value of 50 usually produces better images in less render time than Terragen 4.0.

Because of the above change, the "Quality" parameter on Easy Cloud and Cloud Layer V3 is now called "Ray-marching quality" in the GUI. It is no longer an overall quality control.

The default value for ray-marching quality on Easy Cloud has been reduced from 0.75 to 0.5 for faster rendering in most cases.

Reduced one of the main causes of variance in clouds that causes flickering, where clouds are lit by specular highlights or high values of "glow power" in the atmosphere or surrounding cloud layers. Now that this has been improved, you might be able to use lower settings for "Cloud GI quality" and that will reduce render times.

In Render GI settings on the GI in Clouds tab there is a parameter called "Cloud GI max ray depth". This applies to Cloud Layer V3 and Easy Cloud. It limits the maximum ray depth at which cloud voxel scattering includes light from other parts of the scene. If you have many cloud layers in the scene it's especially important to keep this number low (e.g. 1 or 2) to prevent long render times due to light interactions between cloud layers. This part of the renderer should be improved in future to allow higher ray depths without excessive render times.


Masking input for Easy Cloud. Not only can this be used to control the placement of clouds, you can also use it for interesting effects like making parts of the clouds more wispy or adding more variety to their shapes.


Removed an unnecessary source of noise in atmosphere, especially noticeable in relatively short rays or when using a small number of samples. In many cases atmospheres will now render more accurately and with less noise.

Atmospheres no longer have a parameter to control sample jittering; samples are always jittered.


Changed how the RTP samples/refines the image. This improves parallelism towards the end of the render, reducing total render time.

Changed how the RTP chooses how many threads to use on systems with 24 or more threads (12 or more cores with HT), to reduce the CPU load without sacrificing speed on hyper-threaded systems.

Changed how the 3D Preview in non-RTP mode chooses how many threads to use for various passes, reducing the CPU load but also improving speed, especially on hyper-threaded systems with 24 or more threads (12 cores with HT).


32-bit EXR for rendered images: When saving EXR images from the Render View, you can choose between 16 bit (half float) and 32 bit (full float) precision. We also added an EXR Options button to the render node's Sequence/Output tab, next to the TIFF Options button. You can use this to choose between 16 bit (half float) and 32 bit (full float) for EXR files rendered with Render to Disk and Sequence Render (including command line rendering).

32-bit EXR for heightfields: Heightfields saved to EXR now save to 32-bit float precision.

When saving heightfields to EXR, a single-channel EXR is produced with data in the "Y" channel.


Fixed some problems with the interpolation of GI cache samples at render time (affects renders with cache files and without cache files).


Pixels are updated with final anti-aliased quality more frequently while rendering is in progress. Pixel reconstruction has been optimised so this shouldn't add much to render times. Some renders will finish slightly faster than before.

Boosted the speed of some renders by ignoring bump mapping in certain types of GI and reflection rays where we believe it's unlikely to be important to the final image.

New command line args -oxsubfolders and -oxsubfolders=no which override the "create subfolders" option in the project's render node.


Merge Shader has a new option to select between different texture spaces that are used when evaluating the inputs. They are designed to solve problems with aligning displacement with colour/shading. Different modes work best in different situations.


New shader: Smoothing Filter Shader. This asks upstream shaders to smooth away details at the specified scale. The scale can be modulated with a function input. However, it only works in a few specific cases at the moment. We need to modify the code for each shader to make it react correctly to the smoothing request. Currently only three shaders support smoothing: Power Fractal Shader v3, Cloud Fractal v3 and Fractal Warp Shader. We'd like to add smoothing support to more shaders in future.

"Obey downstream smoothing filters" is an option you can turn on or off for each Power Fractal Shader V3.


Power Fractal Shader V3: "Better colour continuity" and "Better displacement continuity" parameters on the Tweaks tab. When enabled, the shader uses more precise math to remove C1 discontinuities in the 'variation' feature. It also changes how the smoothing of ridges and gullies is performed (in Perlin Ridges, Perlin Billows and Perlin Mix flavours) to give nicer results. "Better_displacement_continuity" is enabled automatically for newly created nodes, but not for existing ones.

Image Map Shader: When you switch to Camera projection the shader automatically enables "position_center" and sets the position to (0.5,0.5,0.0). As in previous versions, it also sets the size to (1,1). You still need to adjust the size parameters match the aspect ratio, but all other settings should be good.

Image Map Shader: When you switch to UV Projection the shader automatically sets the position to (0,0,0). As in previous versions, it also enabled "position_lower_left" and sets size to (1,1).

Reflective Shader: Prevents negative roughness when using a roughness function. Negative results are now clamped to 0.

Transform Input Shader: Added "Use undisplaced space" option.

Transform Merge Shader: Added "Use undisplaced space" option.


Light Source and Spotlight have parameters to enable/disable "light surfaces" and "light atmosphere" just like Sunlight has.

Some parameter labels have changed in Sunlight, Light Source and Spotlight nodes.

Image File Processor (Professional Edition only) has an option to apply some experimental HDR processing.


Fixed bug #578: Wireframe and texture previews were incorrectly clipping when "Use vertical fov" was selected on the camera.

Fixed bug with RTP projection when "Use vertical fov" was selected on the camera.

RTP displays elapsed time (seconds and tenths of a second) if more than 5 seconds have elapsed, or if finished.


Changes to the update checker system. When software updates are available for download, the window that shows the updates has changed. Recommended Updates (Release builds) are shown separately from Optional Updates (Frontier builds). If maintenance has expired and there are new versions that fall outside of the maintenance period then it also gives you a button to renew your maintenance.

Other changes to the update checker and update notification system.

When using Gather Project, the "Project Assets" folder is now called "Project_Assets" (has an underscore).

Some changes to the handling of license key files. In some circumstances Terragen will attempt to update key files with new information from the server at

View menu and 3D Preview context menu no longer show the item to open the 3D Preview in a new window. This will be added back in a future release.
Just because milk is white doesn't mean that clouds are made of milk.


As promised, Terragen 4.1 will be a free update, even if your maintenance has expired. Some of these fixes are too important to hold back and we want everyone to benefit from them.

We're expecting to release 4.1 this month.

Just because milk is white doesn't mean that clouds are made of milk.


Great news! Looking forward to this.
Cheers, Klaus
/ ASUS WS Mainboard / Dual XEON E5-2640v3 / 64GB RAM / NVIDIA GeForce GTX 1070 TI / Win7 Ultimate


That is quite a read and looks like there are some nice changes.
Looking forward for the update.


Great news! Glad to see Voronoi speed improvements, I always loved the result but hesitated to use it due to the higher evaluation times. Also, great to see speed improvements for v3 clouds.
Many thanks!





Can't wait to play with the update!  Thanks for the list of changes. Do you guys see any VDB support in the future?


Yes, we are experimenting with VDB support. No ETA yet. Are you interested in import or export?

- Oshyan


Hello Oshyan,
If I may add my voice to the discussion, vdb export will be a massive game changer. We use Terragen and Arnold and it can be tricky when you want to replicate clouds shadows on an arnold rendered asset, a city for example.
Another situation where it can be handy is, an asset passing through cloud or fog. It will be very useful to export some lower definition of the clouds with maybe the ability to choose the part of the volume you want to get back in Maya, Houdini... This can be used to render matte or extra passes to finetune the integration.

I don't really see a situation where I would like to render the VDB exported in another package. Terragen is way better than everything I've tried in term of realism.


That's definitely great feedback and info! When we do support VDB, it will likely first be for export, so I'm glad that will be helpful for your use cases.

- Oshyan


(04Dec20) Ryzen 1800x, 970 EVO 1TB M.2 SSD, Corsair Vengeance 64GB DDR4 3200 Mem,  EVGA GeForce GTX 1080 Ti FTW3 Graphics 457.51 (04Dec20), Win 10 Pro x64, Terragen Pro 4.5.43 Frontier, BenchMark 0:10:02


We're rolling it out slowly, but yes some users will have it available already. If the initial launch goes well, we'll make it official. It should be pretty well tested by now though. :)

- Oshyan


Had no time to test it all but i like the smoothing filter. Looks like a good addition.