I think it's a Glitch

[Bh_GuruCharan]

In AutoCAD 2025 when I try to subtract 2 cylinders it did not and it shows there are no solids, region, surface and I kept on clicking the same thing even it was showing the same error but all of a sudden it subtracted and then I undid it and tried again to check if it was working or not but it did not work. Then I tried Union and that worked perfectly and again when I try to separate it is not separating. I am suffering this issue from a month.

Any Help!

[Ed.Jobe]

Post a sample drawing and a video of what you're doing.

[Bh_GuruCharan]

No, but just now I've uninstalled 2025 and downloaded 2024 

[AVCPlugins]

Are you sure that you are choosing solids for the Subtruct command? There are 2 requests: the first one requests the main (large) solid, and the second requests the subtractive solid.

[Bh_GuruCharan]

Yes sir, when I converted them to solid and subtracted only some random are getting subtracted and the other which are opposite to the subtracted one's are a converting solid and when I use separate solids it is not separating.  I have sent a video could you please assist me with this and mention me where I committed a mistake

[Kent1Cooper]

It's a little hard to tell in the video, but it looks to me as though you are not completing the selection of the Solid to Subtract from, before selecting what you want to Subtract from it.  You can select more than one thing.  It looks like you are selecting the ring and a sphere under the what-to-Subtract-from selection, when what you should be doing is selecting the ring and hitting Enter/space to complete the selection, before selecting a sphere to Subtract from it.

[AVCPlugins]

You write that you did not model these solids, but converted them. It is likely that you are experiencing conversion glitches. I see that the solids look strange, the spheres are not entirely smooth, and there are extra lines on the cylinders. It is quite possible that AutoCAD actually cannot work with such damaged objects. This is a very common case when users try to use polygonal models from foreign programs. Just create new solids. Simple solids like these are remodeled in seconds.

[Bh_GuruCharan]

when i did what you said first that subtracted and again i undid it to recheck whether this is a right way but again it is showing the same  

[Bh_GuruCharan]

I remodeled it but it did not help 

[Kent1Cooper]

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@Kent1Cooper wrote:

....  You can select more than one thing.  ....

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... for both selections.  You can select more than one thing to Subtract from, and after you've finished that selection, you can select more than one thing to Subtract from it [or them] -- you don't need to Subtract each sphere from the ring separately.  So if they're really all 3D Solids, and their volumes really overlap, you should be able to:

1)  Select the ring as the object to Subtract from;

2)  Enter/space to complete that selection;

3)  Select all the spheres to be Subtracted from the ring, together:

4)  Enter/space to complete that selection.