Solution
STP file is a neutral file that can be opened by any MCAD software. If you are able to open and visualize the 3D Dimensional Drawings correctly on MCAD software but it is having issues on SOLIDWORKS, it may be due to the software Settings:
- Follow the path Changing Tools >> System Options >> Import >> General and uncheck "Enable 3D Interconnect", then check "Solid and Surface" and "Knit surface(s)".
These settings were tried on the SOLIDWORKS online free trial, so these settings may appear slightly different on a Full-Licensed version.