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    [Plugin] Import OBJ with Materials v2.1 20131118

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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! πŸ˜’
      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 β€” 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 β€” 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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              • N Offline
                notareal
                last edited by

                Here is a model that seems to fail http://www.fileden.com/files/2009/5/30/2461193//dragon_scene_OBJ.rar (From CGTalk Frosted Glass Challenge). Maybe it's a bit large... but simlab obj importer seems to handle it.

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

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                • honoluludesktopH Offline
                  honoluludesktop
                  last edited by

                  TIG, Wow, nice piece of code. Lots stuff I have to learn, like next, case, when, def file.run(par1, par2), etc. Makes the code look more compact and easy to read. Oh well, if I looked here before starting what I am working on, I may not have understood:-)

                  Some of the stuff that's driving me nuts when writing importers, is that different exporters do not format the data exactly. SU's DxfIn treats "10", and " 10" equally, and many exporters ignore the convention that is " 10". I don't know if I should go back and fix my code to read "10" or not. It's no problem for my use, and would like to "share", but am concerned about posting something that may not work for some.

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                  • TIGT Offline
                    TIG Moderator
                    last edited by

                    honoluludesktop
                    A DXF has alternating lines for 'code' and 'value'.
                    So if it's an odd-numbered line then it's always 'code' and if it's an even-numbered line it's always the previous line's code's 'value'...
                    It's a DXF convention to indent the 'code' number, BUT it's not necessary and any importer should strip off leading spaces anyway...

                      0
                    SECTION
                      2
                    HEADER
                      9
                    etc
                    

                    is the same as

                    0
                    SECTION
                    2
                    HEADER
                    9
                    etc
                    

                    To see a DXF 'parser' look at my DXF Text Importer http://forums.sketchucation.com/viewtopic.php?p=194488#p194488
                    πŸ€“

                    TIG

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                    • honoluludesktopH Offline
                      honoluludesktop
                      last edited by

                      OK, thanks, I will look at it. I may have to wait for a complete rewrite to parse the 'code'. Isn't some of that done in the Obj translator? I couldn't tell since I am not at all familiar with Obj.

                      When I think about it, any translator can be a modular app., just as you did with the text importer as a supplement to SUs DxfIn. My own interest has been limited to very basic geometry, and dealing with the anomalies of my Cad's DxfIn/Out. It suits me since I use SU exclusively for visualization and modeling, and Cad for functional diagramming and production drawings. Accordingly, I only require the basic geometry to pass between SU and Cad.

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                      • O Offline
                        onesimo
                        last edited by

                        hi tig! thanks for the importer. its working perfectly for me on my archmodels.
                        i should have tried it when i first saw the post. thanks so much and i really appreciate your work.

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                        • O Offline
                          onesimo
                          last edited by

                          hi tig! im using 3ds max design 2011. when i open/obj import my exported file the textures are not showing.. it seems my .mtl file is different from the one posted (the one with the building). thanks!


                          my exported file from 3ds max

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                          • KrisidiousK Offline
                            Krisidious
                            last edited by

                            I imported an Obj file and the uvw map came in perfectly.

                            objimporter02.jpg

                            but some geometry was lost... any ideas on why?

                            objimporter01.jpg

                            By: Kristoff Rand
                            Home DesignerUnique House Plans

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                            • TIGT Offline
                              TIG Moderator
                              last edited by

                              @onesimo said:

                              hi tig! im using 3ds max design 2011. when i open/obj import my exported file the textures are not showing.. it seems my .mtl file is different from the one posted (the one with the building). thanks!

                              The MTL file has the lines

                              Ka 0.0000 0.0000 0.0000
                              Kd 0.0000 0.0000 0.0000
                              Ks 0.3500 0.3500 0.3500
                              

                              they should read

                              Ka 0.0000 0.0000 0.0000
                              Kd 0.3500 0.3500 0.3500
                              Ks 0.0000 0.0000 0.0000
                              

                              The Kd value sets the material's RGB color in the original MTL file it is [0,0,0] = 'black'
                              If you swap the Kd and Ks values and it renders 'gray' as expected...
                              Only the 'Kd' value is read by the SUp importer - the other twp 'K' values involve reflectivity and spectral info that SUp can't use and are superfluous...
                              Also if an MTL material has an image_file defined at the end of its text_block that will be used as its 'texture', overriding any RGB 'color' - but this material does not have a texture.
                              When you make an OBJ file check that its MTL file's 'Kd' is set to RGB otherwise it will be 'black'.

                              TIG

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                              • TIGT Offline
                                TIG Moderator
                                last edited by

                                @krisidious said:

                                I imported an Obj file and the uvw map came in perfectly.
                                but some geometry was lost... any ideas on why?

                                The OBJ importer should import all available geometry described in the file - sometimes with very convoluted meshes it can fail, but it rarely 'misses' stuff out - in fact it's more likely to try and tie vertices together that don't join in the original with extra geometry!
                                If you import the same file into another app - like Blender? - is it still missing parts?
                                If so perhaps the export didn't pick up parts in the first place πŸ˜•
                                What app made the OBJ file originally?

                                TIG

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                                • KrisidiousK Offline
                                  Krisidious
                                  last edited by

                                  @tig said:

                                  @krisidious said:

                                  I imported an Obj file and the uvw map came in perfectly.
                                  but some geometry was lost... any ideas on why?

                                  The OBJ importer should import all available geometry described in the file - sometimes with very convoluted meshes it can fail, but it rarely 'misses' stuff out - in fact it's more likely to try and tie vertices together that don't join in the original with extra geometry!
                                  If you import the same file into another app - like Blender? - is it still missing parts?
                                  If so perhaps the export didn't pick up parts in the first place πŸ˜•
                                  What app made the OBJ file originally?

                                  it came from AC3D, I tried the file in 3Dmax and it's all there. it's no biggy, I don't need to do it. I was just trying it out.

                                  By: Kristoff Rand
                                  Home DesignerUnique House Plans

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                                  • TIGT Offline
                                    TIG Moderator
                                    last edited by

                                    Kristoff

                                    Can you PM me the OBJ/MTL etc [zipped].
                                    I'd like to see if I can find out the cause anyway... πŸ€“

                                    TIG

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                                    • TIGT Offline
                                      TIG Moderator
                                      last edited by

                                      Kristoff

                                      I got the 'Ford' OBJ file by PM.
                                      It imported fine for me... IF I set the units to 'meters' - it also then comes in at the correct 'size'!
                                      If you use 'mm' it is tries to make some edges that are 1000 times too small 0 as you might have seen in other threads that guarantees that geometry fails to be made. SUp / OpenGL doesn't like anything smaller than about 0.1mm...
                                      The importer reads the OBJ file's 'header' and if it has 'units=' in it then that is given as the default displayed in the dialog as it starts, otherwise it defaults to 'inches'.
                                      In the case of this 'Ford' OBJ there's no header info at all, so you need to take a guess - trying larger scale units should always make geometry as the 0.1mm is never likely but of course the imported object might then be the wrong 'size'.
                                      Meters are a common unit in non-US made OBJs...
                                      So, panic over - try it in 'meters' and it should work fine... πŸ€“

                                      TIG

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                                      • KrisidiousK Offline
                                        Krisidious
                                        last edited by

                                        damn counting with 10's burned me again... (hits self in head meter not millimeter!)

                                        awesome plugin. I also love the groupstoobj.rb ...

                                        By: Kristoff Rand
                                        Home DesignerUnique House Plans

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                                        • E Offline
                                          eloiraiol
                                          last edited by

                                          Because the images do not appear in the trial, only show the textures in SketchUp itself. Where is a picture is blank!

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                                          • TIGT Offline
                                            TIG Moderator
                                            last edited by

                                            @eloiraiol said:

                                            Because the images do not appear in the trial, only show the textures in SketchUp itself. Where is a picture is blank!

                                            Please explain your problem another way... I don't understand πŸ˜•

                                            TIG

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