14 Replies Latest reply on May 24, 2011 4:37 AM by Simulacrum_de

    3D PDF transparency PNG sampling issue

    Simulacrum_de

      Hi, could this sampling bug please be fixed, so that the white seams are not visible anymore? Michael

            www.simulacrum.de/temp/SamplingError.pdf

       

      ScreenShot1673.jpg

       

      www.simulacrum.de/temp/SamplingError.pdf

        • 1. Re: 3D PDF transparency PNG sampling issue
          Gazzzzzzzz

          Hi Michael,

          Zomming in, the antiaisling (the blend of pixels between leaves and the background) looks quite large ?

          In your graphics program (I assume PS) can you reduce the amount of antiaisling?

          Regards

          Gazzzz

          • 2. Re: 3D PDF transparency PNG sampling issue
            Simulacrum_de Level 1

            The white seams are the problem. Like you can see at the screenshot, the seams are only at some areas visible. If the bark of the root is behind the leaves, than no seam is visible. It's not a problem of the used texture (than a seam would be visible always), the Acrobat reader has a sampling bug.

            • 3. Re: 3D PDF transparency PNG sampling issue
              Simulacrum_de Level 1

              Hmmm, no answer. Is this not the support forum? Where should I report the problem? I need the bug fixed, since I want to send my clients perfect 3D PDF solutions.

              • 4. Re: 3D PDF transparency PNG sampling issue
                Simulacrum_de Level 1

                That's an useless forum, if Adobe doesn't answer. Waste of time.

                • 5. Re: 3D PDF transparency PNG sampling issue
                  Gazzzzzzzz Level 1

                  Tetra 4D have taken over the

                  3D PDF development - Try here

                  http://www.tetra4d.com/

                   

                  cheers

                  Gazzzzz

                  • 6. Re: 3D PDF transparency PNG sampling issue
                    Simulacrum_de Level 1

                    :)

                     

                    Thank you Gazzzzz, I send a bug report to the Tetra 4D team. Now I'm curious ... .

                    • 7. Re: 3D PDF transparency PNG sampling issue
                      Gazzzzzzzz Level 1

                      Humm, I'm not sure the antialising issue is in the 3D PDF generation side OR the error is in the PDF Reader?

                      If generation side it's Tetra 4D if it's the Reader it's still Adobe.  Good Luck

                      Gazzzz

                      • 8. Re: 3D PDF transparency PNG sampling issue
                        Simulacrum_de Level 1

                        Generated is the the PDF per Simlab Composer, but since at Composer and other 3D software the texture is good looking and bug is visible at special places of the view only, I suppose so the Acrobat reader must be fixed.

                        • 9. Re: 3D PDF transparency PNG sampling issue
                          David A Rees Adobe Employee

                          Hi Michael,

                           

                          Think I've seen this problem before. Thanks for the file. Loaded it - and it looks like all the leaves are one object. I think Reader sorts objects - but not polys within objects. Sorting all the polys could be really slow. So sometimes the polys are drawn in an order that works for opaque surfaces, but shows the issue you see for transparent materials. Looks like for some of the branches the polys interpenetrate - which would need very fancy rendering to fix.

                           

                          One solution you could try is break out the branches or individual triangles into separate objects. This might be what the other renderers mentioned are doing. It would get a better looking model without having to wait for changes in Reader. It would take a bit longer to draw, but you have control over what to sort or not so could balance performance with improved looking rendering.

                           

                          Thanks,

                          David

                          • 10. Re: 3D PDF transparency PNG sampling issue
                            Simulacrum_de Level 1

                            Hello David,

                             

                            thank your for your answer. I tried the workaround trick - it works

                            better than before, but if the model is moved around, the sampling error

                            is flickering sometimes. Attached my 3D PDF with exploded branches.

                            I hope the bug can be fixed, since I'm very curious to use 3D PDF for my

                            clients. It's a nice medium for communication.

                             

                            Regards,

                            Michael

                             

                             

                            Am 17.05.2011 19:23, schrieb David A Rees:

                            Hi Michael,

                            >

                            Think I've seen this problem before. Thanks for the file. Loaded it - and it looks like all the leaves are one object. I think Reader sorts objects - but not polys within objects. Sorting all the polys could be really slow. So sometimes the polys are drawn in an order that works for opaque surfaces, but shows the issue you see for transparent materials. Looks like for some of the branches the polys interpenetrate - which would need very fancy rendering to fix.

                            >

                            One solution you could try is break out the branches or individual triangles into separate objects. This might be what the other renderers mentioned are doing. It would get a better looking model without having to wait for changes in Reader. It would take a bit longer to draw, but you have control over what to sort or not so could balance performance with improved looking rendering.

                            >

                            Thanks,

                            David

                            >

                            • 11. Re: 3D PDF transparency PNG sampling issue
                              David A Rees Adobe Employee

                              Hi Michael,

                               

                              Thanks for the feedback. Do not see the model. A URL might work better? Ideal way to determine the issue is with the simplest model possible. Don't know what you see now, but guessing 2 triangles would be sufficient. If the triangles intersect, no easy way to fix this, and better to pre-process in a modelling tool to move them apart or split the triangles so no intersection, and place each triangle in a separate object. If pre-process every time the user loads 3D in Reader, can significantly add to model load time.

                               

                              David

                              • 12. Re: 3D PDF transparency PNG sampling issue
                                Simulacrum_de Level 1

                                Hi David,

                                 

                                you can dowload the new PDF from here:

                                 

                                www.simulacrum.de/temp/SamplingErrorExploded.pdf

                                 

                                and here are two screenshots there you can see a little movement and the

                                changing look:

                                 

                                www.simulacrum.de/temp/ScreenShot1716.jpg

                                www.simulacrum.de/temp/ScreenShot1717.jpg

                                 

                                If this example isn't good to find the bug, I could more simplify the

                                model. Please let it me know.

                                 

                                Michael

                                 

                                 

                                Am 17.05.2011 23:13, schrieb David A Rees:

                                Hi Michael,

                                >

                                Thanks for the feedback. Do not see the model. A URL might work better? Ideal way to determine the issue is with the simplest model possible. Don't know what you see now, but guessing 2 triangles would be sufficient. If the triangles intersect, no easy way to fix this, and better to pre-process in a modelling tool to move them apart or split the triangles so no intersection, and place each triangle in a separate object. If pre-process every time the user loads 3D in Reader, can significantly add to model load time.

                                >

                                David

                                >

                                • 13. Re: 3D PDF transparency PNG sampling issue
                                  David A Rees Adobe Employee

                                  Hi Michael,

                                   

                                  Thanks for the model. Definitely some improvement.

                                   

                                  Just as you say, I still see the issue. Looks as if you made individual branches into objects. I isolated parts like 3DGeom~46 - it's made of 6 faces, and from most orientations looks fine, but from some look bad. Again it's back to the sorting algorithm. Now the objects have fewer triangles, it's more likely the back most poly is drawn first, then the next - resulting in a good look. Still, sometimes the front most triangle will be drawn first.

                                   

                                  You could try decimating the objects further. 1 triangle per object would give a perfect look. As some of the triangles are almost co-planar, you could try 2 adjacent triangles per object, and would very rarely get artifacts. Usually you woulkd see them when the branches are close to edge on. It looks like the largest change in normal direction is along the main axis of each branch - i.e. the triangle seam that follows the thickest wood of which the branch is composed - so that would be a suggested first place to split the object in two or 4. It's a tradeoff of quality vs file size.

                                   

                                  How does it look if you have just 1 or 2 triangles per object?

                                   

                                  David

                                  • 14. Re: 3D PDF transparency PNG sampling issue
                                    Simulacrum_de Level 1

                                    Hi David,

                                     

                                    I'm using Rhino3D for NURBS modeling and the Rhino mesh tools are quite

                                    basic only. The example tree is only a typical example of objects I use

                                    to fill my scenes. So I can't easy change the polygons. What do you

                                    think, will Acrobat handle objects like this is the near future or are

                                    objects like this a general problem for 3D PDF?

                                     

                                    Regards,

                                    Michael

                                     

                                     

                                     

                                    Am 18.05.2011 21:19, schrieb David A Rees:

                                    Hi Michael,

                                    >

                                    Thanks for the model. Definitely some improvement.

                                    >

                                    Just as you say, I still see the issue. Looks as if you made individual branches into objects. I isolated parts like 3DGeom~46 - it's made of 6 faces, and from most orientations looks fine, but from some look bad. Again it's back to the sorting algorithm. Now the objects have fewer triangles, it's more likely the back most poly is drawn first, then the next - resulting in a good look. Still, sometimes the front most triangle will be drawn first.

                                    >

                                    You could try decimating the objects further. 1 triangle per object would give a perfect look. As some of the triangles are almost co-planar, you could try 2 adjacent triangles per object, and would very rarely get artifacts. Usually you woulkd see them when the branches are close to edge on. It looks like the largest change in normal direction is along the main axis of each branch - i.e. the triangle seam that follows the thickest wood of which the branch is composed - so that would be a suggested first place to split the object in two or 4. It's a tradeoff of quality vs file size.

                                    >

                                    How does it look if you have just 1 or 2 triangles per object?

                                    >

                                    David

                                    >