Render to picture viewer from plugin crash

popandchop

Hey guys,

This is probably a very simple question and i suspect to do with threading. I have a little workflow tool i'm working on and have this Render to Picture Viewer button.

The code behind this button is as simple as this

if id == BTN_SceneRenderPictureViewer:
            
            self.PrintStatusMessage('Rendering to Picture Viewer.')
            self.Close()
            c4d.StopAllThreads()
            time.sleep(0.1)  # Wait a bit to ensure the dialog is closed before rendering
            c4d.CallCommand(12099)

However this causes Cinema to crash. I've tried recreating the Render to Picture viewer function but this was seems much simpler so would be great for it work - any help appreaciated

Thanks alot,
Will

ferdinand

Hello @popandchop,

Welcome to the Maxon developers forum and its community, it is great to have you with us!

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About your First Question

The question is impossible to answer in this form, we would need something concrete (a plugin and a scene which crashes for you) or a time stamp of a submitted crash report.

What you do there is this code snippet looks a bit unusual. I assume from the screen shot that you are inside a GeDialog, the code looks a bit like this could be GeDialog.Command or Message. Please read the Threading Manual, invoking an event, e.g., a command, is forbidden off-main thread. But in a dialog you are usually on the main thread (but you should still check with c4d,.threading.GeIsMainThread()). What is also rather odd, is what you call there:

if id == BTN_SceneRenderPictureViewer:
    self.Close()             # This will shut down the dialog, think of it as a return statement.
    c4d.StopAllThreads()     # This is generally the biggest nuke you can drop on Cinema 4D and should
                             # be avoided. But in this context (a dialog that has been closed) this
                             # seems extra dangerous. Why are you doing this?
    time.sleep(0.1)          # This makes things even worse, as it increases the chance that the dialog
                             # has been destroyed before the last line of this function has been 
                             # executed. If I had to guess, this is probably crashing here.
    c4d.CallCommand(12099)

I assume you hve a modal dialog and that you run into issues with opening the picture viewer due to that? Either make your dialog non-modal (in GeDialog.Open) and then first send the command and then close the dialog or keep using a modal dialog and detach the code from the instance of the dialog.

import c4d

class MyModalDialog (c4d.gui.GeDialog):

    BTN_SceneRenderPictureViewer: int = 1000

    # ...

    def Command(self, cid: int, msg: c4d.BaseContainer) -> bool:
        if cid == MyModalDialog.BTN_SceneRenderPictureViewer:
            MyModalDialog.CloseAndAction(self, 12099)
        return True

    @staticmethod
    def CloseAndAction(dlg: "MyModalDialog", cid: int) -> None:
        """Closes the passed dialog and executes a command.

        Args:
            dlg (MyModalDialog): The dialog instance to close.
            cid (int): The command ID to execute after closing the dialog.
        """
        if not dlg or not c4d.threading.GeIsMainThread():
            return
        
        dlg.Close()
        c4d.CallCommand(cid)

if __name__ == '__main__':
    dlg = MyModalDialog()
    dlg.Open(c4d.DLG_TYPE_MODAL, defaultw=400, defaulth=300, title="My Modal Dialog")

Cheers,
Ferdinand