I've extended my earlier parametric lamp shade to actually fit a nice old lamp where the cloche was broken.
In particular, the stand notch parameter allows the bottom to be inward rounded so it can be fixed with screws or "clicked" into something.
The parameters I've used are shown in the gallery.
I've put some more detail on how I made it into Instructions.
I've calculated this one with quality setting "2" (which took 100s on Chrome on a newer laptop).
Link is still http://beta.gigmade.com/2015/04/beautiful-curves/
Update: very high resolution now available.
Download customized STL at
The two "piriform height constant" results in an object where the rounded shapes length is roughly double the value you enter, in mm.
There's a vertical and horizontal scale for the overall end thing in case you want to adjust the end result without changing other values.
This is a thing you have to print in "vase-mode" and no bottom wall.
In Ultimakers "cura" slicer e.g., the setting to check is called "spiralize outer contour", and uncheck "solid infill bottom". Then it should work.
As you might see, I've used an Ultimaker with a custom fan (google "tapir shroud"), but I don't think it this made a big difference.
Instead, to be on the safe side I've gone down to ridiculously low speed at the place where there is a large outward angle - I think it might have been between 15-20mm/s (at 210°C temp PLA).
I'm sure it could work faster but I just didn't want to risk it. Print took about 8-9 hours with these settings.
The light it gives is really nice but be careful: at least with PLA you should definitely use a LED light, with a regular 40W bulb the thing is going to slowly deform.