Editing STL Files on SketchUp
Step 1: Installing SketchUp and SketchUp Plugins
If you haven't install SketchUp by now, click on the following link: here It will take you to, the download page, choose the SketchUp version that works for your computer and then download it. If you do it right, you will see something like
To install plugins Click on Window tab then choose Extension Warehouse option, then you can search for the plugin that you want. To import and export STL files we need to install a plugin that converts STL files to Sketchup files. On the Extension warehouse search for "STL import plugin" and then choose SketchUp STL by the sketchup team.
Setp 2: Importing a STL file to SketchUp
Once you opened the file, the file will be added to the SketchUp default working page. This working page gives you a clear view of 3D space but it also has a default human figure which you don't rely need. To erase the human figure, first select the figure by clicking on it. Then, click on the "Erase Button" and move it on the the figure. Still, it is hard to see the imported model so click on the button with the magnifying glass icon on the top right. This button allows you to zoom in or zoom out.
Step 3: Softening Edges
This option allows you to manipulate the use of softening within your model. More explanation can be found here http://help.sketchup.com/en/article/114941 .... To use this feature, go to "Windows" then select "Soften Edges" and change the angle to get a more soften shape and this feature allows you to hide lines to create a more clear view.
Step 4: Creating Vertical Planes and Intersect the Faces with the Model
Now select the line drawing feature to create a rectangular line that can be used as a plane to intersect the figure. Once we have the rectangular figure, click on "Shapes" and then construct "Rectangular" planes.
Now select all the models including the plane by clicking on the figures triple times, then right click on the selected figures and choose "Intersect Faces" and choose "With Model" by mouse-over on this feature.
Step 5: Delete the Middle Part between the Two Planes including the Planes
Now convert each part to a separate component. To do this, select the object, right click on the selected object, and choose "Make a Component" option.
Step 6: Joining the Two Parts and Make them One Component
Step 7: Smoothing Edges and Cleanup Work
In this step, you hide unnecessary lines to create a clear view. To do this, select the lines you don't want on your final model, then right click and select "Hide" option.
In addition while joining the two pieces there may be an open surface to create the surface connect lines using the line option. If you do this right, you endup something that looks like the following:
Step 8: Converting SketchUp File to a STL File
Go to "File" and then select "Export STL" and then give the file name and click on "Save". If you can't see this option, it means that you have not installed the plugin, so please go to the first step we discussed to install the plugin. After that, you will be able to see the plugin and complete this step
The stl file can be install https://github.com/dewnetu/LofaroLabsFiles-/blob/master/STL%20files/ArmtoSteelwithRoundedMiddlePlates.stl