Vector shapes with rounded corners imported with sharp corners

[BryceLTaylor]

Some vector sprites have shapes with rounded edges in 2.0 that are possibly imported from other software. In 3.0 they will be imported with straight edges.

Examples:
The play button and white background pattern on the title screen in here:
https://llk.github.io/scratch-gui/develop/compatibility-testing.html#203392290

The shape of the tank parts in this project
https://llk.github.io/scratch-gui/develop/compatibility-testing.html#132801606

[SAODTHEKING]

not only that! alot of them have weird collision boxes.
try this project in 2.0 then 3.0
https://scratch.mit.edu/projects/198901436/
you will see u cant move in 3.0 thats because the collision boxes of the level are larger than normal

[BryceLTaylor]

From this issue: #2780 (comment)
I have figured out how to reproduce creating rounded corners in 2.0

Create a new sprite
Convert it to Vector
Choose the Square tool
Ensure that the square is in the hollow mode
Increase the Stroke Thickness
Choose the paint bucket tool
Set it to one of the gradient options (it doesn't matter which, but it can't be the solid color)
Set both colors to the same color (not required, but it's what people often do)
Click on the Stroke of the box
Note: the corners become round

When importing projects like this into 3.0 the corners are not drawn rounded.

Here is a repro project: 239683784

[BryceLTaylor]

Here is a project teaching people how to do this: https://scratch.mit.edu/projects/140325920/
It has a few extra steps (like holding shift to keep the shape square). My repro steps above are a more minimal set.

[BryceLTaylor]

It seems that if you "gradient trick" a line created with the line tool, the line doesn't appear on the stage in 3.0. See this project:
https://beta.scratch.mit.edu/#240180579

[thisandagain]

Tracking in scratchfoundation/scratch-paint#394