Render Preview gives different results from Final Render View Window (Lighting)

Started by EwanD, May 04, 2017, 06:07:02 pm

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Hi All,

I've had this problem in terragen 3 and it still seems to be here in terragen 4. I wonder if someone could help me understand.
My clouds seem to react differently in the render preview window than the final renders in the render view. I'm talking about the tonal range and the way they are being illuminated or are in shadow.

with Raytraced Preview

without Raytraced preview

In both of these there is a difference between the end renders and the preview image. I prefer the look of the preview images, I am getting more shadow in the mid level clouds. The tonal range seems more balanced in both preview renders, the final render looks incorrect to me.

This is just rendering with the default out of the box settings. I've rebuilt the scene and started with new render nodes to check if it was that.

Could it just about the render settings of the preview view? Is there anyway I can mimic the render settings of the preview view exactly?

Any help at all would be much appreciated, its been driving me crazy for a long time!



Also i've attached the scene file here.


thanks again


You might want to read this thread:,21728.msg218519.html#msg218519
Maybe we are lucky and RTP and Final Render look more similar in the (near) future.

For the time being we have to render crops to be sure, I guess.

On the other hand there are some settings I change to get closer to the preview:

- turn of "Use voxels for shadows" in the "Optimisation" tab of the cloud
- reduce the "Edge sharpness" on the "Main" tab of the cloud
- raise the "Ambient" value on the "Tweaks" tab of the cloud (0.1 - 0.5) or something
- use the "modulator" slots on the "Tweaks" tab of the cloud
- increase the "Light received from environment", "Enviro light" value on the clouds "Lighting" tab

Did the Final render you posted really take 1 hour?
If so, a more accurate preview would be indeed very helpful...

It`s tedious and time consuming to work around this.
cheers, Klaus
/ ASUS WS Mainboard / Dual XEON E5-2640v3 / 64GB RAM / NVIDIA GeForce GTX 1070 TI / Win7 Ultimate


Hi KlausK,

thanks very much for your suggestions, they are definitely helpful in getting it closer. Its a shame the mid level clouds don't have the same underside shadow as the preview still. But I guess with some tweaking it could be achieved.

I thinks matts suggestion in the other thread is really what im after.

"I could address this by having an option to render final atmospheres with the same GI engine as the RTP"

But actually its not just a difference in the rtp as i said this was an issue in terragen 3 as well with the regular preview. Its just more noticeable with the rtp. But really i think the rtp atmosphere settings look more balanced than the final render settings.

thanks for your help


Bump in 2020 with v4.4...still happening! Any updates to this phenomenon?
Senior Cinematic Artist


Quote from: ackdoh on January 07, 2020, 05:26:43 pmBump in 2020 with v4.4...still happening! Any updates to this phenomenon?

Hi Ackdoh, welcome to the forum. This has not been solved yet. Our recommendations are still to use RTP for cloud modelling and approximate lighting only. Renders are needed to see final lighting.
Just because milk is white doesn't mean that clouds are made of milk.