You can use a 3D model viewer to open an SKP file provided that it supports the SKP file format as input. If you want a free tool that lets you open and view an SKP file, you can use the ones mentioned in this post. You can use free software like pCon.planner to visualize a 3D model from an SKP file on Windows PC. Or, you can use a free online tool like the Sketchup web app to open an SKP file in a web browser. We have discussed these SKP viewers and editors in detail, so you can use check them out here.