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Trouble creating PDF U3D with desired lighting behavior.

Mar 13, 2008 8:29 AM

I am automatically generating U3D and PDF U3D from within my 3D app but am at a loss as to how to produce PDF U3D with well behaved lighting using the CAD Optimized Lights lighting scheme.

Lighting and shading look OK for the initial view, however, when rotating the 3D model away from the initial view it appears that the infinite light which should be attached to the camera remains stationary as shading becomes darker (near black).

I am using Adobe Acrobat 3D Version 8.1.2 to view U3D PDF and can reproduced both the undesired and desired behavior using the Acrobat 3D U3D import tool.

To reproduce the undesired behavior using Acrobat 3D to import U3D:

Tools > Advanced Editing > 3D Tool
Add 3D Content
Browse... and select U3D file
Default Lighting: CAD Optimized Lights
Default Rendering Style: Solid
Other settings left at default values
OK
Acrobat 3D Conversion
3D Conversion Settings: Custom
Check Pass U3D file through unchanged
OK
Click to activate 3D

To reproduce the desired behavior repeat the same process as above but in the Acrobat 3D Conversion dialog Uncheck Pass U3D file through unchanged.

Any ideas what Acrobat 3D is doing to "fix" the U3D data and what I need to do to generate U3D data that Acrobat 3D will light correctly?

For U3D creation I am actually exporting edge/face graphics and product structure to IDTF and using the open source IDTFConverter program to convert to U3D.

Thank you in advance for any help!

Dave
580 Views   4 Replies   Latest reply: mvid, May 18, 2012 8:35 PM
 
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  • Steve Small
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    1. Steve Small,
    Mar 13, 2008 9:33 AM   in reply to (Dave_T_Smith)
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    David,

    It sounds like you're fixing the problem yourself by unchecking the "Pass U3D Through Unchanged" box. It also sounds like the U3D generator you're using is changing the lighting values that you see in your original application. Are these points correct?
     
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    2. (Dave_T_Smith),
    Mar 13, 2008 10:48 AM   in reply to (Dave_T_Smith)
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    Thank you for your reply.

    To clarify, one of my requirements is to generate PDF U3D without requiring Acrobat 3D, so using the Acrobat 3D importer is not a solution for me, though it was useful to prove the difference in behavior is caused by a difference in the binary U3D data and not something wrong with the PDF objects I am generating.

    At this time I am not creating any lights in IDTF or U3D files as these are just temporarily generated files which are removed once the target PDF U3D file is created. It is my understanding that when the CAD Optimized Lights or any other (except Lights from file) lighting scheme is active then any lights that may be in the U3D data are ignored.

    Any ideas or suggestions welcome, thanks again!

    Dave
     
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  • keee1234
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    3. keee1234,
    May 8, 2012 7:16 PM   in reply to (Dave_T_Smith)
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    Hi Dave,

    Do you have any solution of this problem? I have the same problem as you. I put U3D in PDF file using my program but the default light always none. I need to set the default lighting scheme to the "Lights from file" or "CAD Optimized Lights". So can you please tell me what the solution you have? Thanks.

     
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  • mvid
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    4. mvid,
    May 18, 2012 8:35 PM   in reply to keee1234
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    > I put U3D in PDF file using my program

     

    Read PDF spec and take a look at libharu (latest versions) opensource library for examples of embedding 3D models into PDF.

    Or be more specific on what steps did you take in your program to set lights, so that someone can spot problems in your approach.

    Providing useful advice knowing nothing more but that your program does not produce desired results requires advanced telepathy skills.

     
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