How can i fip faces(inverted normals)?

[windbladezero]

thats it, how can i do it in sketchup, the model its fine, and when i import it to dae, remains fine, but when i import it again to stl(sketchup doesnt have an stl exporter integrated and the plugin i found, doesnt work, so i downloaded a program that exports from dae to stl)
but the stl get a message error about the inverted normals and the model ends with "empty output", and i really need it
but i dont know how to invert/flip the faces/normals

[Roger]

@windbladezero said:

thats it, how can i do it in sketchup, the model its fine, and when i import it to dae, remains fine, but when i import it again to stl(sketchup doesnt have an stl exporter integrated and the plugin i found, doesnt work, so i downloaded a program that exports from dae to stl)
but the stl get a message error about the inverted normals and the model ends with "empty output", and i really need it
but i dont know how to invert/flip the faces/normals

Select the inverted faces and right click. Then click on "Reverse Faces."

[dukejazz]

[plugin] Vbfr.rb
by D. Bur

Sections: Edit ; Materials - Rendering

Three automatic tools to quickly orient/invert faces if they are not "pointing" in the correct direction("blue syndrom")

[TIG]

View your model in a Style with a distinctly colored back-face-material - say bright-blue.
Now view your model in Monochrome mode and any reversed faces will stand out.
As has been said select them and right-click context-menu Reverse-Face to flip them.
There are also many scripts available to flip such faces from simple flippers to swapping over front/back materials as well.
If the face forms part of a 'solid' [probably required in the export you are doing] then selecting one correctly oriented face and using the context-menu Orient-Faces will flip all of the connected faces to be the same orientation - however if it's not solid you can get odd results as three faces on one edge can never be oriented consistently - one will also be 'wrong' !