I’m getting the following error whenever I try painting on my terrain with 9 textures present in the paint texture editor. Not sure if this is as intended? I never get this error any other time when working with terrains. Then if I try painting with the 9th texture and then use undo it leaves a black texture in the textures place.
Failed to create Object Undo, because the action is too large. Clearing undo buffer
UnityEditor.DockArea:OnGUI()
I am still getting this error and now its happening randomly on one of my terrains that only has 7 textures. Very frustrating… Could this be a memory issue ?
Currently the undo integration with terrain has issues and in order to avoid enormous memory usage when working with terrain the undo system has a memory usage limit. This limit is quickly reached when working with terrain.
We are already aware of this issue, but currently we don’t have any one assigned to work on the issue.
Unfortunately there is no work around for you.
Thank you for your answer. Hopefully it will be fixed in the future. I guess I will have to make due for the meantime.
I’m also having this problem, and not only does it not undo, but replaces textures i’ve worked on with other ones, which makes me lose hours of work. has there been any progress on this, or jessee03, have you found any workarounds?
Hey peeps. Sorry to resurrect this thread, but I’m getting this same error message when baking a Very Large Scene with Umbra. I’d also appreciate any updates on this issue.
Going bump this. Over a year old since the last answer and I’m getting this. With the 64bit client can we get more memory or an option to allow more memory to be used?
Still no work around for this, you’d think they would address this issue. Bloody annoying.
I know this is an old thread, but I was having this issue myself where I would get this warning, and if I tried painting the (large) terrain again Unity would crash. Googled for days before I figured out a solution, so I figured I’d share it in case someone else is having similar issues.
Open the Preferences and under GI Cache, click Clear Cache and increase the Maximum Cache size.
At least that worked for me!
not work for me 
its can be easily fixed by clicking on your splatmap by Repeat to Clamp and back.
Those do not work for me. I am using 2018.1.f6 , and I must set build setting to Iphone which can not use normal view mode.
I also have this issue in 2019.2.10
Its crazy that this issue still exists.
The ability to set the memory limit should be included at the absolute minimum. With 23GB free on my machine I should be able to dedicate a little more memory fat to the issue.
5 years later, is anyone looking into it yet???!!!
doesn’t seem like it. Interesting.
I noticed this issue pops up if you crank the texture resolutions (on terrain data) too high. Somewhere around 2048 control texture resolution it appears.
Still happening in 2019.3.14f1, Terrain Tools 3.0.1.
I’ve got the same issue in 2019.3.0f3, using microsplat.
Seriously? I guess Unity doesn’t care about painting terrain. I’ve got the same issue in 2019.4.13f1, also using Microsplat.
Same problem. Different year.
