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    [Plugin] Import OBJ with Materials v2.1 20131118

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    • TIGT Offline
      TIG Moderator
      last edited by

      @jsteacy said:

      TIG, I tried using your script to import .OBJ files from this website http://www.modelplusmodel.com, and it doesn't work. Note that it didn't work for the Simlab Importer as well, something about negative indexes of the faces. Can you look into it? Also reading through the posts trying to get a better understanding of the .OBJ file type. Does every OBJ file need an MTL file for materials and textures?

      That site's free-sample bird 3DS file imported OK [in Pro] - see below...
      BUT the OBJ file format... ๐Ÿ˜’
      To answer your questions first...
      If there is no MTL file then there are no colors/materials in the resulting mesh.
      If there is an MTL file but no images in the defined ../folder_path/file_name then there objects with materials specified will only get the color without the texture.

      The f 123/123 124/124 125/125 is the correct way for a face to be specified in an OBJ file - this face is triangular, and uses vertices 123/124/125 [v] and the equivalent texture vertices [vt].
      I can't see why their OBJ file format uses negative values at all !!! ๐Ÿ˜•

      My OBJ Importer is not foolproof... BUT can you point me at exact problem [OBJ[MTL] files... or PM me them ?
      I can change my code to trap for any negative values for 'face indices' [see below]... BUT the imported object might end up being rubbish anyway ? I suspect that we need a miracle ?? ๐Ÿ˜ฎ Capture.PNG

      TIG

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      • J Offline
        Jim
        last edited by

        negative vertex references are legal in the .obj format.

        f -1 -2 -3

        this just means use the vertexes defined 1, 2, and 3 lines previous. Negative index values mean a relative offset from the current line. (I think. ๐Ÿ˜’ ) Not sure if it includes all lines, or just 'v' lines in the count, though.

        Hi

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        • N Offline
          notareal
          last edited by

          "BUT the imported object might end up being rubbish anyway ? I suspect that we need a miracle ??"
          I believe it can be done... well just tested and Thea did import that 'F06 House bird' OK... sorry I don't have internal details how importer will actually handle this model.

          Welcome to try [Thea Render](http://www.thearender.com/), Thea support | [kerkythea.net](http://www.kerkythea.net/) -team member

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          • J Offline
            Jim
            last edited by

            Since Ruby has negative array indexes already, and the .obj is imported in at least a recognizable format, it may be something simple like an off-by-one error for negative indexes.

            Hi

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            • J Offline
              jsteacy
              last edited by

              I tried all of them including the house bird, and nothing gets imported. This is what I get from the console after I click the units to import to:

              Error; #<ArgumentError; Cannot convert argument to Sketchup;;Point3d>
              C;/Program Files/Google/Google SketchUp 7/Plugins/obj_importer.rb;278;in `add'
              C;/Program Files/Google/Google SketchUp 7/Plugins/obj_importer.rb;278;in `run'
              C;/Program Files/Google/Google SketchUp 7/Plugins/obj_importer.rb;278;in `map'
              C;/Program Files/Google/Google SketchUp 7/Plugins/obj_importer.rb;278;in `run'
              C;/Program Files/Google/Google SketchUp 7/Plugins/obj_importer.rb;208;in `each'
              C;/Program Files/Google/Google SketchUp 7/Plugins/obj_importer.rb;208;in `run'
              C;/Program Files/Google/Google SketchUp 7/Plugins/obj_importer.rb;329
              C;/Program Files/Google/Google SketchUp 7/Plugins/obj_importer.rb;329;in `call'
              

              hope that helps

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              • TIGT Offline
                TIG Moderator
                last edited by

                So if the face-indices are 'negative' then we work backwards through the face vertex lists ? - i.e we reverse the array of v's, and take the abs value as the index ? ๐Ÿ˜•

                TIG

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                • J Offline
                  Jim
                  last edited by

                  Line 248:

                  
                  values.each do |v|
                  w = v.split("/")
                  vvv = Integer(w[0])
                  if vvv <= -2 # this 
                    vvv += 1
                  end
                  face<<Integer(vvv)
                  face_uvs.push(w[1].to_i)if w[1]
                  
                  

                  And maybe look at fill_from_mesh instead of a dd_faces_from_mesh. # Line 302. Probably left over from someone else..

                  587.png

                  I'm shocked it actually seems to have worked - it was just a hunch.

                  Hi

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                  • TIGT Offline
                    TIG Moderator
                    last edited by

                    Here's a slightly different version that I was working on independently - it also works !
                    http://forums.sketchucation.com/viewtopic.php?p=172790#p172790 [v1.7 has fill from mesh changes too]Capture.PNG

                    TIG

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                    • thomthomT Offline
                      thomthom
                      last edited by

                      Any ideas what caused these glitches? http://forums.sketchucation.com/viewtopic.php?f=323&t=20584&start=75#p264875

                      Thomas Thomassen โ€” SketchUp Monkey & Coding addict
                      List of my plugins and link to the CookieWare fund

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                      • TIGT Offline
                        TIG Moderator
                        last edited by

                        Thomthom, I assume you are referring to the size/units ?
                        If the file has a '# units = meters' line then the importer defaults to 'meters' [or whatever it says].
                        If it doesn't then it defaults to 'inches'.
                        However, as it starts a dialog lets you choose whatever units you'd like to use anyway [preset to those default units].
                        Some meshes don't form the tiny faces if the units are set too small - e.g. if you were to choose 'mm' when it was made in 'meters'. So if you are unclear about the units and none are specified then you can try out alternatives until you get a proper mesh without holes...
                        The reason the tool has three options is speed - 'as mesh' is fast but can fail when the OBJ code is convoluted; otherwise the textures can be added or not as desired.
                        The old sizing issue seems resolved.
                        PS: I can't tested your problem 'van' OBJ/MTL because PPartner010000.jpg wasn't in the zip file?
                        But I can see that its geometry seems a bit messed up around the side windows and the image file-names have spaces in them which confuses the MTL parser. I thought that you were 'recommended' to avoid having spaces in these paths/names - however, manually editing the MTL and the corresponding image-names so they are without spaces fixes that... BUT the 'PPartner010000.jpg' file is still missing altogether - see the Ruby Console error reporting ๐Ÿ˜•

                        TIG

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                        • TIGT Offline
                          TIG Moderator
                          last edited by

                          Busy today! Heres 1.8 - Trapped for spaces in image-names/paths.
                          http://forums.sketchucation.com/viewtopic.php?p=172790#p172790

                          TIG

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                          • thomthomT Offline
                            thomthom
                            last edited by

                            @tig said:

                            Thomthom, I assume you are referring to the size/units ?

                            No - it was the messed up geometry you noticed. You see it in the screenshots I posted - with the red circles.

                            @tig said:

                            PS: I can't tested your problem 'van' OBJ/MTL because PPartner010000.jpg wasn't in the zip file?
                            But I can see that its geometry seems a bit messed up around the side windows and the image file-names have spaces in them which confuses the MTL parser. I thought that you were 'recommended' to avoid having spaces in these paths/names - however, manually editing the MTL and the corresponding image-names so they are without spaces fixes that... BUT the 'PPartner010000.jpg' file is still missing altogether - see the Ruby Console error reporting ๐Ÿ˜•

                            The OBJ was initially created by SketchUp - then edited textures in PhotoShop.

                            I've attached the missing texture.

                            Will try v 1.8


                            missing texture

                            Thomas Thomassen โ€” SketchUp Monkey & Coding addict
                            List of my plugins and link to the CookieWare fund

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                            • thomthomT Offline
                              thomthom
                              last edited by

                              Even with 1.8 some geometry is messed up. Seem to be the same faces.

                              Thomas Thomassen โ€” SketchUp Monkey & Coding addict
                              List of my plugins and link to the CookieWare fund

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                              • TIGT Offline
                                TIG Moderator
                                last edited by

                                I see the messed up UV textures.
                                I re-imported it as 'mm' and the messed geometry went.
                                BUT I had to edit the faulty UV mapped parts manually.
                                As it's symmetrical a quick mirror/copy of the correct panel on the other side fixed them.
                                The 'Badge' is messed up though - did you map that on separately ?
                                I've no idea why just those few parts fail to map properly ๐Ÿ˜•
                                VAN.PNGVAN.skp

                                TIG

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                                • thomthomT Offline
                                  thomthom
                                  last edited by

                                  I import in mm - but it's not just the UV being messed up. It's the actual geometry.
                                  Notice that for the incorrect mapping the face is split diagonally-crossing itself - as opposed to the mirrored side.
                                  When you compare against the 3ds import you see that Max does not do this.

                                  I did not do anything to the mapping other than take the OBS into PS and adding the text on the side of the van. The model came from a pre-modelled and pre-mapped third party model.

                                  I wonder if it's the order of the vertices that's abnormal in these cases... ?

                                  Thomas Thomassen โ€” SketchUp Monkey & Coding addict
                                  List of my plugins and link to the CookieWare fund

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                                  • TIGT Offline
                                    TIG Moderator
                                    last edited by

                                    The cross-threading of the faces' vertices into 'bowtie' triangles - which then probably mess up the UV-mapping - must be in the OBJ file itself [?].
                                    The OBJ Importer simply uses the f n/n nn/nn/ nnn/nnn... values to form the faces and mapping ? Unfortunately unless you can reproduce the problem in a file with relatively few faces it'll be all but impossible to plough through the data to find the problem instances... [+460+ faces here?].
                                    I was hoping that the OBJ had some -ve face indices that were causing the problem which recent versions might have solved... but NO! ๐Ÿ˜’
                                    In SUp export the ordering of a face's vertices shouldn't be a problem as they should always return ordered, and in the correct 'clockwise-ness' for the face's normal direct ?

                                    TIG

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                                    • J Offline
                                      Jim
                                      last edited by

                                      The vertexes in the 'f' line are out of order for whatever reason.

                                      Creates a "bow tie":

                                      Sketchup.active_model.entities.add_face([0,0], [1,1], [1,0], [0,1])

                                      Hi

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                                      • thomthomT Offline
                                        thomthom
                                        last edited by

                                        So it's the OBJ data that's invalid... but Max manage to deal with it somehow.

                                        I'll compare against the raw output from SU and see if it's SU or PS that mangles the geometry.

                                        Thomas Thomassen โ€” SketchUp Monkey & Coding addict
                                        List of my plugins and link to the CookieWare fund

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                                        • thomthomT Offline
                                          thomthom
                                          last edited by

                                          It's SU generating the odd vertex order. Here's the OBJ directly from SU:


                                          SU Export

                                          Thomas Thomassen โ€” SketchUp Monkey & Coding addict
                                          List of my plugins and link to the CookieWare fund

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                                          • TIGT Offline
                                            TIG Moderator
                                            last edited by

                                            Could you PM me the original textured SKP - I have a new embryonic OBJ-Exporter that might NOT do this glitch ?

                                            TIG

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