topic Re: why does extrude sometimes create a surface instead of a solid? in AutoCAD Forum

why does extrude sometimes create a surface instead of a solid?

jetted4 — Tue, 01 Sep 2020 16:21:20 GMT

I am new to 3D modeling. I am trying to create a bent bracket with a hole in it. I know how to extrude and then union and subtract to get the desired outcome, but when I extrude the various shapes, the rectangular base and the circle that will become the hole both extrude as solids exactly how I'd like, but the main part of the bracket extrudes as a surface instead of the solid that I want.

I looked up how to convert a surface into a solid and the answer I found was to use the thicken command on the surface, but that just extends the surface outward and leaves the interior hollow still which is not what I want. I want it to extrude as a solid just the way the circle and rectangle shapes did.

I attached a DWG showing my original 2D drawing and next to it what I ended up with by extruding.

Thanks 🙂

Re: why does extrude sometimes create a surface instead of a solid?

fatal.error — Tue, 01 Sep 2020 16:42:06 GMT

The drawn polyline isn't closed. Select it, change it's Closed value to Yes and repeat the extrusion.

Re: why does extrude sometimes create a surface instead of a solid?

jetted4 — Tue, 01 Sep 2020 17:04:06 GMT

Two for Two. Thanks again 🙂

Re: why does extrude sometimes create a surface instead of a solid?

imadHabash — Tue, 01 Sep 2020 17:11:17 GMT

Hi,

also ... you have to watch your Extrude MOde option :

Command: EXTRUDE
Current wire frame density: ISOLINES=4, Closed profiles creation mode = Solid
Select objects to extrude or [MOde]: MO
Closed profiles creation mode [SOlid/SUrface] <Solid>:

Re: why does extrude sometimes create a surface instead of a solid?

Fleiscal01 — Thu, 03 Sep 2020 15:17:50 GMT

I had the same problem but when I open up the properties to close it, that is not an option. Is there something I need to do beforehand to make all the lines and arcs act as one (I have them grouped but I know thats not it)

Re: why does extrude sometimes create a surface instead of a solid?

jetted4 — Thu, 03 Sep 2020 15:22:53 GMT

I had a 2nd object that I ran into that problem with.

The first one, I changed Closed in the Prop menu to Yes and that fixed it.

The 2nd object it refused to change Closed to yes, so I exploded it and the rejoined each of the pieces together one by one and then was able to extrude it as a solid just fine. When I moved it, I discovered that there had been a tiny piece of the original drawing remaining where it had been so that tiny segment must have been joined to the polyline in a funny way that was preventing it from being able to treat it as a closed loop.

Re: why does extrude sometimes create a surface instead of a solid?

Fleiscal01 — Thu, 03 Sep 2020 15:48:53 GMT

That Worked! Thanks! Did you have to "Join" the holes a certain way to get it to not extract that section? (Sorry, my terminology is probably wrong- I'm used to working in fusion where all of this is pretty intuitive)

Re: why does extrude sometimes create a surface instead of a solid?

jetted4 — Thu, 03 Sep 2020 15:57:54 GMT

Great 🙂

If you have holes of any shape that you don't want to be part of the resulting solid, you need to extrude those as separate entities and then Subtract them from the object you want to keep.

(with the Subtract command, it asks you to first select the object you want to Subtract *From* (i.e., what you want to keep), then 2nd you select what you want to subtract/remove.

Re: why does extrude sometimes create a surface instead of a solid?

Fleiscal01 — Thu, 03 Sep 2020 16:00:05 GMT

PERFECT! It worked!!! Thank you so much! Ive been fiddling with the subtract tool for the past hour, I think I was clicking in the wrong order.

Re: why does extrude sometimes create a surface instead of a solid?

giwa.olayinkasamuel — Thu, 27 Jan 2022 01:42:01 GMT

It worked, Thanks!

Re: why does extrude sometimes create a surface instead of a solid?

giwa.olayinkasamuel — Thu, 27 Jan 2022 01:43:26 GMT

It worked like fire, thanks 👍

Re: why does extrude sometimes create a surface instead of a solid?

nazrulazril — Fri, 19 Dec 2025 09:13:23 GMT

thank you @fatal.error my issue also resolved using your method. Thank you.