Hey there, in this tutorial, I'm going to show you how to give OBJ files shadows in Blender to make your 3D models look more realistic. First, import your OBJ file into Blender by going to File > Import > Wavefront (.obj). Once your model is in the scene, let's focus on adding shadows. Start by positioning your model in the 3D space where you want the shadows to be cast. Next, add a light source to the scene by clicking Shift + A > Light > Point or any other type of light you prefer. Position the light so that it casts a realistic shadow on your model. Now, let's adjust the shadow settings. Click on the light source and go to the Object Data Properties tab. Under Shadow, enable 'Contact Shadows' and adjust the Softness and Distance to achieve the desired shadow effect. You can also experiment with the strength and color of the light to further enhance the shadow. Finally, render your scene by clicking on the Render tab and selecting Render Image. You'll now see your OBJ file with realistic shadows! By following these steps, you can give your 3D models depth and realism in Blender. I hope you found this tutorial helpful. Happy modeling!