realism of cornel box (Cycles vs Keyshot)

Hi folks,

here is a rendering I did in Cycles compared with Keyshot.

Personally I feel the shadows in the Keyshot rendering right are to dark for a box.

What is your take?

What happened to Keyshot’s green color? It does contain too much blue in it; much more than Cycles image. That could be the reason why contrast seems higher compared to Cycles.

What’s the bounce number in Keyshot? It almost looks like there’s some AO on top of the GI. Then again… Keyshot has never really provided “accurate” results IMO.

I would be astonished if I found out that I spent over 1K on a render engine that didn’t provide world-class realism and lighting prowess (One could perhaps render the Keyshot box in BI even). Though perhaps it really is true that the avid 3D artist crowd isn’t so much its target market.

In this case (for those who want speed, realism, and control), the Arnold engine would give you a much better deal for around the same price.

Keyshot doesn’t target even close to the same market as Arnold. Keyshot is mostly intended for product rendering. Until recently you couldn’t even use real light sources (only HDR) and I’m still fairly certain it doesn’t have support for most animation features.

EDIT: Actually, according to their website, you STILL can only light with HDRI images.

In my opinion it still is a joke IBL engine. But they claim photo realism and physically accurate results.
When I looked at the cornel box I started to feel some something was wrong here.

I must say also in finale rendering the engine got pretty fast, the box is faster than in KS than Cycles,
but I start to get the suspicion thats because they take shortcuts and not provide a physically accurate model.

BTW it looks the render engine is set to 2 diffuse bounces in KS. Compare this to the Cycles engine when I set it to a similar low level - welcome dark corner …

EDIT after setting values to good KS is still pathetically slow …
And the result is not much better - I increased GI values to max here. This is sad preview is like full quality rendering OMG


Cycles render looks dull–like there is a film over the image. I’d say the Keyshot render is producing a greater dynamic range. It is more vibrant and looks better for a “product render” IMHO.

Cylces dull? ah curve correction ect?

a lot of out of the box images from ks are dull as well!

Just commenting on my observation of the images in the first post. Maybe Cycles is 100% accurate, but to me, I prefer the Keyshot look in that post.

Is Cycles accurate? i find myself cranking up the exposure and playing with the film types to get an image that “pops.” Out-of-the-box renders often seem kind of blah (to me).

Do you know if the render result you see is the raw rendering or does KS internally adjust / color correct the image?

based on that they trick around in some areas I would not be surprised here as well.

Renders in a true 32-bit linear color space without tone mapping or correction are supposed to look like that.

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thats what I thought.

Referring to the images in the first post again, it is not just the corners that are darker in the KS render–the center of the walls appear to have more illumination than in the Cycles render. How do you calibrate the light source energy between the two cases? What about material property differences or shader differences?

Regarding the 32-bit color space render is “supposed to look like that” comment, I am confused because there is sRGB gamma correction at the end, no? So, at the least, the assertion is incomplete, (if true).

Not trying to troll here. My preferred renderer is Cycles for a number of reasons. I have been disappointed in some of my my results with Cycles and am always interested in how to improve it.


I think KS automates a lot and also does not give you the raw rendering. So if the contrast looks better thats I very much assume because the images got adjusted automatically. In Blender you get a raw image and then you can correct it in Blender or Photoshop.

I found the curve correction to be pretty useful but simple exposure and gamma can do it.

Here in this image I did such an adjustment of the screen and you see the difference compared to the first image.

Also KS seems to either use some AO or really low level of diffuse bounces which can add more contrast because edges are darker but I rather have the feeling they set the max bounce so low so it renders faster.

I see. They are much closer now. KS must do some post processing out-of-the-box. Thanks for the explanation.

How are these two scenes lit?

The one on the left seems to use a standard lamp (invisible to the camera) - whereas the one on the right appears to use a visible mesh emitter on the ceiling. Could this be the reason for some of the observed differences?

I just learned about the ‘Sample Line’.

In cycles it is an area light not a mesh light! But mesh light gave same result in Cycles.