Hey there, if you've ever come across a 3DM file and wondered how to open it, you're in the right place! Here's how to do it in a few easy steps. First, you'll need to have the appropriate software installed on your computer. The most common program for opening and editing 3DM files is Rhinoceros 3D. If you don't have it yet, you can download and install it from their official website. Once you have Rhinoceros 3D installed, simply double-click on the 3DM file, and it should automatically open in the program. If it doesn't, you can also open the software first and then navigate to the 'File' menu to select 'Open' and choose the 3DM file from your computer. Now you can explore and edit the 3D model to your heart's content! And there you have it, that's how you open a 3DM file. Happy modeling!