I was experimenting with the "L-system" filter, and found that the generated structure always ends up beyond the top of the page. Is it possible to assign the coordinates where you'd like the start point of the L-system to be at? Or, alternatively, re-assign the default start coordinates? TIA.

IIRC the object is rendered at the center of the screen, and you can use Step length option to make it smaller. You can also scale the object down after it was rendered

Hmm... I understand the controls I found in the dialog box for the extension, but what you wrote about rendering at center of screen doesn't match what I found while using it - unless, of course, the rendering of an L-system generates a default vertical offset of about 250 pixels upward for placement of the visible points placed on screen. Without exception, every time I used it, the starting point of the displayed L-system structure was displaced from screen center in that manner.

Let me correct myself, the starting point of the pattern is placed at the screen center, the position of the final object depends on its shape/formula.

I just took another good long look at the contents of the L-system extension dialog box and the page of its "Help" tab, with what you'd written in mind. I don't see anything there that would result in a vertical displacement of the L-system away from a screen center starting point. I think this displacement might be a design flaw, although I don't think it really constitutes being a "bug" because the extension does seem to generate accurate L-systems as advertised. It's just they're not conveniently placed re. the work area.

I find that many Inkscape extensions render their content somewhere outside the screen boundary. It's really frustrating, because most of them have the fantastic Live Preview. But the preview is also off the screen, and is therefore useless. I'm not sure I can say that any extension I've ever used has rendered its content in the middle of the screen. They're either on the screen and not centered, or off the screen entirely. Maybe one or 2, now that I think of it, do actually render in the center. But most don't, and most of those are off the screen entirely.

Check your xml file for any transform before running an extension as the presence of a transform may cause the output to be displaced. This applies to many of the extensions and once you are aware of this the extensions should perform "as advertised".

Check your xml file for any transform before running an extension as the presence of a transform may cause the output to be displaced. This applies to many of the extensions and once you are aware of this the extensions should perform "as advertised".

Aaahhh, thanks druban!
And when I find the transformation in XML editor, what should I do? Delete it? Would that not affect whatever I had transformed previously??