How to change Control–Command–Space bar?

Vendors are supposed to check for hard wired keyboard commands in the OS so they don't assign the same keystroke in their apps. But I think this one is kind of recent, so may have not been a problem before.

But anywho, this is actually very simple. It goes right back to the System Preferences as I noted above. The command for the Emoji placement is right there in the Finder menu:

All you need to do is assign it a different keystroke. Open the System Preference and open the Keyboard panel. Click on the Shortcuts tab, and then App Shortcuts. Click the + button to create a new entry.

Make sure to type in the name exactly the same as the OS has it. Then type in any keystroke you want to change it to. Here, I used a keystroke I would very likely never use, need or ever even accidentally hit.

Click the Add button.

That's it. The emoji character palette will no longer appear when you press Command+Ctrl+Space, and your 3D app should do what's normally assigned to that keystroke.

Correct. You just assign a used shortcut something else so you can free up the one Apple used. You can see in my previous post I forced Save As… back to its decades long traditional keystroke of Command+Shift+S.

Hmm, hard to say for sure since the OP doesn't even mention emojis. However, I do see I incorrectly referred to Command+Option+Space rather than Command+Ctrl+Space.

But, you can override it in the System Preferences. Here I added it to take over the system's Command+V for Paste.

That's also how it now shows up in the OS and app menus.

To undo it, just delete the entry you made.

I believe the OP is trying to disable the shortcut for the Emoji Viewer: control-cmd-space ⌃⌘space.

I don't believe there's a way native to the OS. Might have to go to a third-party to intercept and remap that.

It's a default keystroke for Spotlight:

Disable it there, and you'll then be able to assign anything you want to it.

Head to System preferences then keyboard then modifier keys. That's what I did.