In some cases, the [Render Now] window does not appear even after executing the command.
This issue is related to specific settings.
Cause:
The rendering engine in the 3D Options is set to [Legacy Raytracing Engine], which does not support the [Render Now] feature properly.
Solution:
[1] Open 3D Options, go to the Rendering settings.
Change to [Advanced Rendering Engine] from [Legacy Raytracing Engine:].
[2] Click [Add-In Applications] in the [Add-Ins] tab.
In the menu, check the box for [Advanced Rendering Engine].
[3] Click [Render Now] in the [Visualization] tab and confirm that the render window appears as expected.