If you're a fan of MikuMikuDance (MMD) and want to incorporate custom 3D models into your projects, knowing how to open OBJ files is essential. OBJ files are a popular 3D model format that can be used with MMD to bring in custom characters, props, and more. Here's how to do it:

1. Install a plugin: To open OBJ files in MMD, you'll need to install a plugin called 'PMD/PMX2OBJ.' This plugin allows you to import OBJ files into MMD and use them in your animations. You can find the plugin by searching online or visiting MMD community forums.

2. Convert OBJ to PMD/PMX: Once you have the plugin installed, you'll need to convert your OBJ file to a PMD or PMX file. This can be done using the 'PMD/PMX2OBJ' plugin by selecting the OBJ file and converting it to the desired format. PMD and PMX files are compatible with MMD and can be easily imported into the software.

3. Import the file into MMD: After converting the OBJ file to a PMD or PMX file, you can now import it into MMD. Open MMD and go to the 'File' menu, then select 'Load.' Choose the PMD or PMX file that you converted from the OBJ file, and it will be imported into MMD for use in your animations.

4. Adjust the model: Once the OBJ file is imported into MMD, you may need to make some adjustments to the model. This can include scaling, positioning, and rigging the model to work properly within MMD. Use the toolset within MMD to make these adjustments to fit the OBJ model seamlessly into your projects.

By following these steps, you can open OBJ files in MMD and expand your 3D modeling capabilities within the software. With the ability to import custom OBJ models, you can bring a new level of creativity and customization to your MMD animations. Experiment with different models, props, and characters to enhance your projects and bring your creative vision to life in MikuMikuDance.