I use to work with a plug-in ‘superellips’ in Sketchup 8.
See: Draw and Edit Superellipses Interactively in Sketchup - YouTube

How can I draw a superellips in Sketchup Pro 2021?

I would go to Sketchucation and get the Superellipse pluginand install it.

What is that? I need to register with a lot of information and/or to subscribe for / a year?
Can you do better?

What do you mean? You can sign up to Sketchucation at no charge. There are loads of useful extensions available there.

Yeah. I can leave you to figure it out on your own.

I see you went ahead and signed up at Sketchucation anyway.


This leads to: Superellipse - Free Plugins - Regular Polygon
I found that earlier myself, but it is indicaded as ‘not save’
Nevertheless I downloaded and tried to install the extension.
Unfortunately (or ?) Sktechup crashed and I cannot enter anymore.
So I remain witrh the question:
What is that (Sketchucation)?

I just installed it directly from sketchucation in 2021 and it works fine.

Maybe I am doing it the wrong way, but this is what I get:

Something is wrong with your MAC set up.
An RBZ file is a type of ZIP file used by SketchUp to store extensions and associated files etc…
So obviously the Extension Manager should be able to process the RBZ and install its contents for you…

I assume you opened Extension Manager, clicked the Install Extension button…
Did you then find the downloaded RBZ and choose it ?
Did the error message then appear ?

I’ve never seen that error before…
Any MAC users want to chip in ?


I have never seen that message.

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SketchUcation is a long-standing and highly-respected independent SketchUp forum (it actually predates both this forum and the Extension Warehouse). Its Plugin Store hosts hundreds of extensions. Membership is free, though you can opt for a Premium membership for a fee that enables some privileges and shows support.

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I’ve never seen it either.

Tell us the exact steps you followed - leave nothing out - and maybe someone can figure out what is going wrong. I have installed lots of extensions from SketchUcation, both via their own Plugin Store extension and by downloading the rbz and then using Extension Manager, and have never seen the error message you showed.

While you are at it, please correct your forum profile. The specific version of macOS you are running could be relevant, and you should fill in your graphics. You can find out both by clicking the Apple icon at upper left on your screen and choosing “About this Mac” from the menu.

Another point…
The Extension Manager dialog you show seems to be entirely empty ??
It should be populated with a few extension entries which SketchUp always includes [from your ‘ShippedExtensions’ subfolder], copying them into your user’s Plugins folder as SketchUp starts up…

Are you having any other weird issues with Sketchup ?
I suspect that something is fundamentally FUBAR with your installation…

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Would this happen if the user was running from the .dmg instead of having actually installed SketchUp?



Hmm…Strange things can happen when a user does that.

There is a rare occasion when after a crash SketchUp prompts to load extensions. If you say ‘no’ the extension window is empty.
Never been able to reproduce, though.