Render glitches and a request to remember layout upon opening files

Started by tws27, February 14, 2023, 02:56:26 PM

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Hi all,

I use Terragen 4 chiefly to render out skyboxes for old 3D shooters such as Doom (using enhanced source ports) and Quake.  I've had a recurring problem where, when I perform renders, the render will hang, and if I click "Pause" and "Restart", the time for the render will cease displaying and it will just say, "Rendering...".  To get the render to render out fully, I have to periodically click "Pause" and "Restart" to get it to render out up to three square blocks of the image at a time, and then, when it is eventually finished, click "Stop render" and save it out.  When I get this problem, if I try to start a new render, I always get a "Preparing to render..." hang.  

The only way around it that I've found is to close and restart Terragen, and when I do this, it tends to be only a short time before the problem strikes again.  Usually restarting Windows helps, in that it then takes a lot longer before the problem strikes again.  The problem does seem to be more likely to kick in if I am doing something else on my computer while the render is running, but it can strike even when I am not doing anything else but the render.  It doesn't seem to be linked with maxing out my CPU or RAM, as I normally set Terragen to use just 2 or 3 of my 4 CPU cores.

Another request I have is that I would like to have the option to have Terragen remember my chosen layout when I open a new file (e.g. if I'm on Renderers, and I open a new file, keep it on Renderers).  At present, it always takes me to the Terrain layout.  I can appreciate that this is meant to be helpful, for the users who use Terragen 4 mainly for terrain generation, but I only spend around 5% of my Terragen time at most on sculpting terrain, so I get a sense of having to fight the interface.  I know that I'm far from the only Terragen user who uses it more for rendering out skies than for its terrain, though there's the caveat that I don't know if there are many users in my kind of position who haven't just stuck with Terragen Classic as opposed to moving to a paid version of Terragen 4.

No doubt the above rendering issue is making it far more of an annoyance than it would otherwise be.  I'm routinely having to close and re-open Terragen files where I have got part-way through a render before the above render problem sets in.  Whenever I open a new file, it always takes me back to the Terrain layout, and I have to keep changing it back to Renderers every time, and I have to wait for the "Terrain" layout to load before I can switch to "Renderers", whereupon I then have to wait for the Renderers layout to load as well.  It gets frustrating because of the regularity with which I have to keep re-opening files.  Sometimes clicking "Renderers" repeatedly while loading the file works, but at other times it doesn't register my inputs and still sends me back to Terrain.

I have a Intel(R) Core(TM) i5-6500 CPU @ 3.20GHz with 32 GB RAM and am currently running Terragen Creative build 4.6.31.  I have had the same issue with all incarnations of Terragen 4, including the free version that I had several years ago before I upgraded to the paid Creative version, so I don't know if my render glitches are specific to my PC.  If it was a Microsoft updates thing I would expect it to be affecting most Windows users. 

Kevin Kipper

Hi tws27,

Terragen's default behavior at startup or the creation of a new project is to focus on the Terrain layout from the point of view of the camera assigned to the Master renderer.  It does not record the last Layout used for a given project, or intialize to a user defined layout.  However, these are good requests and I'll be sure to add them to our internal features request list.

You indicated that when the render hangs, it doesn't seem to be linked with maxing out your CPU or RAM, but I'm also wondering what Task Manager shows at this point in the render?

Without a project file, it's a bit hard to diagnose the behavior you're describing.  Please feel free to email the project file in question to and we'll take a look at it.


Hi tws27,

I don`t know how often these TG "Layout" behaviour-isms were discussed here over the years...I for one stopped asking and suggesting.

About the rendering problems:
the feeling that TG "slows down" the computer after longer sessions has been described more than once.
Restarting the machine is reported to be the most helpful way to get back to work.
As far as I remember nobody ever could recreate this behaviour and nail it to a specific workflow or node or whatever.

I would suggest to render the skybox from the command line for a change to check, if the problems occur then as well.
Did you ever try that? You can render without starting the GUI which saves a lot of resources.
There is a txt file in TGs program folder ("win_command_line.txt") which describes all the commands available and how to set this up.
So, once you are ready with your skybox setup inside TG, have done all the necessary test renders,
save the scene, close TG and render from the command line.
I always do that when I try to render heavy scenes. Makes a difference.
Good luck!

CHeers, Klaus
/ ASUS WS Mainboard / Dual XEON E5-2640v3 / 64GB RAM / NVIDIA GeForce GTX 1070 TI / Win7 Ultimate . . . still (||-:-||)


Another thing would be to monitor Ram usage, HDD activity etc while rendering.
Is there any slowdown or "filling up" visible? Anything like that...
Look at the Taskmanager while rendering.
Run a RAM Test from Bios or software.

CHeers, Klaus
/ ASUS WS Mainboard / Dual XEON E5-2640v3 / 64GB RAM / NVIDIA GeForce GTX 1070 TI / Win7 Ultimate . . . still (||-:-||)


Yeah, do a RAM test. Sounds like stuff I was reporting when my second DIMM, and then primary DIMM also started failing. Render hangups, no render time, etc. It would hit bad sectors in the flash memory on the DIMMs and just start doing any sort of weird stuff, including rendering just black.

Additionally, TG defaults to storing it's temporary TIFFs on your C drive, if it doesn't have enough space to actually save the progress in temp it will cause issues.


Apologies for not getting back about this sooner. 

While my RAM usage is invariably fine when doing renders, I noticed that the Windows "System" process ntoskrnl.exe was sporadically using 20-30% of my CPU.  Even when I was using only 3 of my CPU 4 cores to render scenes in Terragen, it was enough to max out my CPU usage for significant periods.  I ran a Windows registry scan and Windows determined that some parts of the registry were corrupt and repaired them, and immediately "System" dropped to using 0-1% of CPU.  I haven't been able to verify if this "System" process hogging the CPU coincided with my issue with renders "pausing", but it can't have been helping matters.  I'll be testing this out over the coming weeks to see if I've finally got a solution.


I had a similar issue where rendering scenes in Terragen would utilize only three of my four CPU cores, causing the CPU to reach its maximum for an extended period of time. While render time is happening, make sure there are no DIMM issues or crashes. This issue fixed. Thanks!