UDK scaling issues

Geology and Terrain
#1

Hey guys!

I have a bit of a problem with matching the results that are being shown in WM with the end result in the Unreal Engine (UDK). The general shape is alright but there seems to be a mismatch in the altitude. As you can see in the UDK example the scaling of the Z axis is just going through the roof.

What I did found out is that the Terrain Altitude Scaling in the Project World Settings was set to 2625 m. When I changed it all the way too the right I got a similar result as in the UDK. What I did then is to clamp the end result which kind of fixes the issue but leads me to my question.

What would be the best workflow in this case because clamping doesn’t seem to be the best option. Would it makes sense to just put the Terrain Altitude Scaling to a very high value to mimic the UDK scaling and if that’s the case, Is there someone who know the proper settings in the Altitude Scaling for the Unreal Engine? I guess it’s something between 10000 and 16000m.

Cheers

#2

Although this could work – setting the project scaling really high then clamping it to a lower value – this will negatively impact the precision of your output terrains – if your terrain is scaled to only 25% of the vertical range, for example, you’re giving up 2 bits of precision.

I’m not personally familiar with UDK but you should almost certainly be able to apply scaling within the editor. Perhaps someone else can chime in here, but from the look of what you posted it seems like the terrain is importing as a cubical space – you should be able to apply some Z scaling to match World Machine:

If your WM vertical scale is, lets say, 2400m, and your world is 8000m on a side, then your vertical scaling to apply to the terrain cube would be 2400/8000 = 0.3.

Cheers

#3

I am using UDK also and this scale is not easy. I try to have a 1.5 m/pixel in detail scale

#4

Thanks for your answer Remnant!
It is possible to scale the Terrain in Unreal on the Z-axis. Not sure though if it has any negativ impact on performance, streaming etc.

It would be nice if someone else could share his experience in regards of importing it into Unreal.

Cheers

#5

I set the hight in the Project Settings/General setup/Maximum Elevation

#6

Not quite sure what you mean. I only have the Terrain Altitude Scaling under Project Settings/General Setup.

#7

Keep the terrain at 80% altitude usage (clamp to 10-90%) when you output from WM. This way you can just use the UDK scale tool (X=128, Y=128, Z=16-64 for example) to scale the terrain/landscape down to a reasonable value after import. When you use this approach, the altitude data will remain accurate and undesired “stepping” will decrease. You also gain a more granular control over the landscape painting tool in UDK.

You can also use a software like HMCS or TerreSculptor (Google will find these, if I remember correctly they have been developed by the same person) to make altitude adjustments and output a proper .r16 file for UDK to import.

Also be sure that you use a 16-bit heightmap in UDK. 8-bit works, but the staircase-like stepping becomes extreme in most situations.

#8