Hi James, Thank you for your explanation! Using the argument 'INVOKE_DEFAULT' did work :) but introduces new challenges. My script is about placing a certain number of cameras into a blender scene. Next, I want to iterate over all cameras and have crowdrender render the corresponding frame for each camera and write each frame as png to my hard drive. Using the argument 'INVOKE_DEFAULT' causes crowdrender to start the render process in a non-blocking way which causes troubles: Since I am iterating over all cameras calling bpy.ops.crowdrender.render('INVOKE_DEFAULT') for each iteration blender does not wait for the previous render call to finish and interrupts by starting the current iteration's render call. Example: Image only one camera present in the scene. Iterating over only one camera and starting a non blocking render thread just works fine! Now, let's say we have two cameras. Beeing in the first iteration and calling bpy.ops.crowdrender.render for the first time it will start crowdrender's render pipeline. Meanwhile the script continues (non-blocking way) proceeding with next iteration and calling bpy.ops.crowdrender.render for the second time and interrupting the previous process. Calling blenders bpy.ops.render.render operator without 'INVOKE_DEFAULT' present in its arguments causes blender to block the script until rendering is complete what solves my problem. Does something similar exist for the bpy.ops.crowdrender.render operator?

@James Calling bpy.ops.crowdrender.render throws the following error: File "C:\Users\sebastian\AppData\Roaming\Blender Foundation\Blender\2.80\scripts\addons\suncg_addon\blender\camera.py", line 302, in render_cameras bpy.ops.crowdrender.render() File "g:\Program Files\Blender Foundation\Blender\2.80\scripts\modules\bpy\ops.py", line 201, in __call__ ret = op_call(self.idname_py(), None, kw) RuntimeError: Error: Traceback (most recent call last): File "/Users/jamescrowther/Desktop/Crowdrender/cr_compile/releases/multi OS releases/blender_addon/2.80/crowdrender/src/cr/ui_operators.py", line 3822, in execute ValueError: list.remove(x): x not in list I have tried the following and it works. But that solution does not satisfy my task: Adding the crowdrender.render operator to my UI Panel like so layout.row().operator("crowdrender.render", text="My Render Still") When I click this "My Render Still" button the rendering works! But as stated, that is not the use case I try to solve. I want to call the "Render Still" operation from a script and not by adding a button and clicking this button by myself.

Hello :) Is there an update regarding API support? I am asking because I would like to control the crowdrender via python. In detail, can I somehow invoke the Render Still operator by a python command, like bpy.ops.crowdrender.render() Thank you! Best Regards.