8 Replies Latest reply on Apr 4, 2018 2:11 PM by Greg James

    Reversed Normals - Workflow Question

    Danny Sosa

      This is a problem I have had with Solidworks for as long as I have been using it - random faces on models are inside-out.  This doesn't seem to be a problem when rendering in Soldiworks, but this software does not exist in a vacuum.


      I am using Keyshot to import native Solidworks geometry of glassware.  When rendering with clear materials, the randomly reversed normals show up as ugly inconsistencies in transmission and reflections.  I know I am not the only person with this problem, as I have read plenty of threads about how I am straight out of luck for being able to reverse the normals of individual faces from within Solidworks.


      My question is for those of you who use third party software to render Solidworks models.  How do you cope with this persistent problem?


      (I know this is not a Keyshot forum and I am not here to complain about Solidworks, just trying to circumnavigate this problem and meet my deadline)

        • Re: Reversed Normals - Workflow Question
          John Stoltzfus

          Try the new Visualize, you'll be pleasantly surprised....

            • Re: Reversed Normals - Workflow Question
              Danny Sosa

              Thanks John, I did some reading and it certainly seems interesting.  We are still operating on 2014, but when it comes time to update I will certainly push to evaluate the 2017 release of Visualize as a potential replacement for Keyshot.


              At the moment, replacing Solidworks or Keyshot is not an option.  I am really after something that I can use to edit the normals of a Solidworks model.



                • Re: Reversed Normals - Workflow Question
                  Alan Sweetenham

                  Hi Danny



                  You can install just Visualize 2016 or 2017 on it's own and import models from 2014. You may not get all of the appearances/ textures coming through but it will import the geometry very nicely.


                  Not run into this issue myself but i know Keyshot also has an add in for SOLIDWORKS maybe that will improve things for you?



                  • Re: Reversed Normals - Workflow Question
                    Paul Salvador

                    Danny,.. I'm not a Keyshot user but a past LightWave user.. so, for normals flipping, I would either manually edit/flip them or (if it was a large issue) run a macro (normalize?) to flip them.

                    So, I'm not sure if Keyshot has any edit features/functions/macros to flip normals?

                    Can you export the file to say FBX or OBJ and re-import the FBX/OBJ? ..that is, exporting sometimes normalizes the faces?


                    Anyhow, I don't know what to say about doing this within SolidWorks.. except, keep you blends or fillets clean.. run a check on the model to find/locate problem faces/edges.. and clean them up... and, maybe experiment with facet resolution (image quality) before saving/exporting to Keyshot?

                • Re: Reversed Normals - Workflow Question
                  Josh Brady

                  Sorry, I don't have KeyShot, so maybe dumb question...


                  Do the models that cause problems in KeyShot look OK in the SW graphics window?  Or are they displayed incorrectly there too? 


                  Have you tried inserting a zero offset surface, then deleting the offending face of the model, then knit the surface bodies back together into a solid?


                  Can you upload an offending model? 

                  • Re: Reversed Normals - Workflow Question
                    Danny Sosa

                    Thank you everyone for your feedback and suggestions.


                    Perhaps I should have mentioned this in the first post, but things I have tried are:

                    1. Remodel every way I can think of, including duplicate surface, duplicate body, delete and replace face, intersection curve then revolve, replace model fillets with tangent arcs in sketches, manually draw and constrain sketch lines that were previously created by offset, etc.  Interestingly, the inverted faces are all either fillets or adjacent to fillets.  Deleting the filleted face and replacing it with a loft/boundary surface yields the same results.

                    2. Export as STL, Parasolid, STEP

                    3. Manually edit normals of an exported STL in Blender, then import to Keyshot (Modicum of success, but just an incredible headache. This method destroys the arrangement of multiple bodies)


                    Alan - Thanks for the suggestion.  I will certainly look into Visualize, though it will probably have to wait until next calendar year as I don't have purchasing autonomy.  I have tried the Keyshot importer plugin to no avail.


                    Paul - It sounds like you know what I am dealing with.  Although Keyshot 6 Pro does have a new tool for viewing normals, its usefulness is relegated to making tweaks to the way models are smoothed.  As far as my experimentation and reading have borne out, there is no way to tell Keyshot that it is looking at the inside/outside of a particular piece of geometry i.e. reversing face normals.


                    Josh - Unfortunately, as is so often the case, intellectual property management prevents me from being able to post the models I am working on.


                    I will try the OBJ suggestion this weekend.  If it does not do the trick, I will try to create another model in the same way that exhibits the same behavior.


                    Thank you all.