ID 340523 - ScanlineRender node creates artifacts if Project3D node is reading in large image with a different aspect ratio and the crop is disabled

Problem summary
It is possible to use a large resolution image to project on geometry to create a moving landscape. To make this efficient, Nuke crops this within the viewer's resolution and the information of the entire image is retained as long as the bounding box remains.

If the input image is of a different aspect ratio to the output resolution, this will be cropped by default within the 'Project3D' node before it is processed through the 'ScanlineRender' node. 

The user has the ability to turn 'on' and 'off' this crop value in the 'Project3D' node. The expected result would be the pass through of the projection when the crop is off.

This is not the case and causes the incorrect calculation of the scanlines at the lower half of where the crop starts.

This occurs erratically and more common when first opening a script.

Customer reported version
nuke.10.0v6

Customer reported platform
fedora

Steps to reproduce

Open attached file and look through the 'ScanlineRender' node.

or

1) Start a new Nuke script at 'square_2k' resolution

2) Create a Checkerboard node at 15360 x 8640 (16:9)

3) Create a Transform node and scale to '5'

4) Create a 'Project3D' node and turn 'off' crop.

5) Create a 'Cylinder' node under the "Project3D' node and set uniform scale to '2000'

6) Create a 'Camera' node and connect to 'cam' input of the 'Project3D' node

7) Create 'ScanlineRender' node and connect the 'Camera' to 'Cam' input and the 'Cylinder' to the 'obj/scn' input

8) Create a 'Constant' and connect it to the 'bg' input (see diagram below for node tree setup)
​

​

9) Save the script and re-open the script

10) View the 'ScanlineRender' node
Result: In the viewer you will see the areas that would be cropped if the option was on in the 'Project3D' node will have some artifacting through the scanlines.

Workaround
One workaround is to reformat the large resolution image to that of the aspect ratio of the project (this will not affect the original image, it will just extend image data over the resolution edge)

Based on the above steps, the following steps can be used as a workaround.

1) Create a 'Reformat' node under the large resolution source image

2) Create a new output format that creates the footage at the same aspect of the sequence settings. For example if the source resolution is '15360 x 8640', this means the new resolution will be '15360 x 15360' to match the square pixels of the project resolution.

3) Ensure the resize type is set to 'none'
Result: This creates additional information above and below the image and stops the cropping issue
​

​

Reproduced by support
Nuke 11.1v2 - Windows 7
Nuke 11.0v4 - Windows 7
Nuke 11.0v1 - Windows 7
Nuke 10.5v7 - Windows 7
Nuke 10.5v1 - Windows 7
Nuke 10.0v6 - Windows 7
Nuke 10.0v1 - Windows 7
Nuke 9.0v9 - Windows 7
Nuke 9.0v1 - Windows 7
Nuke 8.0v7 - Windows 7
Nuke 8.0v1 - Windows 7
Nuke 7.0v10 - Windows 7

Earliest version tested
Nuke 7.0v10
- This issue appears to be in all versions of the product

Expected behaviour
When the crop is off in the 'Project3D' node, this should not cause artifacting through the 'ScanlineRender' output, but allow the projection to pass through correctly.

Actual behaviour
When the crop is off in the 'Project3D' node, this creates artifacting through the 'ScanlineRender' output.