If you're looking to import and work with OBJ files in AutoCAD, you're in the right place. Here's a step-by-step guide to help you open OBJ files in AutoCAD:

1. Launch AutoCAD: Start by opening AutoCAD on your computer.

2. Open a New or Existing File: You can either open a new or existing AutoCAD file where you want to import the OBJ model.

3. Go to the Insert Tab: Once you have the file open, navigate to the 'Insert' tab in the menu bar at the top of the AutoCAD interface.

4. Select 'Import': Under the 'Insert' tab, you should see an option to 'Import' files. Click on this option to browse your computer for the OBJ file you want to open.

5. Locate the OBJ File: Use the file browser window to locate the OBJ file you want to import. Once you find it, select the file and click 'Open' to begin the import process.

6. Adjust Import Settings: Depending on the specific OBJ file, you may be prompted to adjust the import settings such as scale, rotation, and insertion point. Make any necessary adjustments and proceed with the import.

7. Place the OBJ Model: After confirming the import settings, you will be able to place the OBJ model within your AutoCAD file. Click on the desired location in your drawing to place the model.

8. Edit and Modify: Once the OBJ model is imported, you can edit and modify it using AutoCAD's 3D modeling tools to integrate it into your design as needed.

9. Save Your Work: After importing and editing the OBJ model, make sure to save your AutoCAD file to preserve the changes.

With these simple steps, you can successfully open OBJ files in AutoCAD and incorporate 3D models into your designs. Whether you're working on architectural projects, product design, or any other 3D modeling tasks, AutoCAD provides the tools you need to bring OBJ files into your workflow.