Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] General Discussion => Topic started by: Nik on 2015-12-02, 17:24:09

Title: DR striped render, missing asset
Post by: Nik on 2015-12-02, 17:24:09

Hello, I found pretty strange behaviour of Corona DR.
I attached render where I intentionally lost textrure on the Sphere. Notice that there is a clearly visible stripe and image splitted horizontally.

I know that there must be no missing assets. This is not the question.
The question is, why render becomes splitted? Corona is progressive render, so I suppose all nodes must render whole image and with some interval these images merging together on master machine.
So if I get one image with texture and one image without it, when I blend them together I will get mix of these images. So in my case whole Sphere must be washed out, but not half of it.

Anyway, can somebody from dev team explain how Corona merging DR passes together? I'm just curious.

Title: Re: DR striped render, missing asset
Post by: Ondra on 2015-12-02, 17:41:10

because the image in DR is being sent in stripes. This is to prevent memory/network overload if one would send for example 5k renders in 1 piece

Title: Re: DR striped render, missing asset
Post by: Nik on 2015-12-02, 18:04:34

Doesn't that means that in my case bottom half of image have more passes than top? Top half if from master only, bottom is merged from two images.
No offence, but I think this is quite wrong behaviour for DR render :) Quality of image must be consistent in each halfs of image.

Title: Re: DR striped render, missing asset
Post by: Ondra on 2015-12-02, 18:29:24

yes, it does. But it will eventually converge if you let it run long enough.

Title: Re: DR striped render, missing asset
Post by: Nik on 2015-12-02, 18:59:53

Please tell me that these stripes are changing positions by time :)

So, if I have gigabit network I can increase "Max pixels to transfer" to 5mpx instead of 0.5mpx and stripes are gone. Ok

Title: Re: DR striped render, missing asset
Post by: Nekrobul on 2015-12-03, 13:25:53

As i noticed image is fully ubdated with dr in some 100-150 pases (depending on how many nodes are conected) the odre nodes the faster you will get image without stripes.

Title: Re: DR striped render, missing asset
Post by: Nik on 2015-12-03, 14:03:51

Sorry if I'm tedious :) I just want to get deeper understanding of this mechanism. I used DR only in VRay with bucket mode, but progressive is different story.

If I start Corona DR with default parameters, then:
1 - Master and nodes PCs starts rendering.
2 - Every 60 seconds all nodes sends 0.5mpx piece of image. All these pieces are blended together on Master PC.

So, why positions of these pieces are static?