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  1. #1

    NewB: Multiple Pictures to 3D geometry w/dimensions (don't need CAD)

    I am a Day One Babe in the Woods to this stuff.

    I'm trying to build a copy of an intake manifold, piping, and supercharger brackets for a V8 engine.

    The parts are simple. Cylindrers, orthogonal blocks, perpendicular holes, etc. where an accuracy of 1/8" would be fine. 3/16" possibly acceptable, and 1/4" excessive.

    I saw most of the discussion was regarding "scanning" which involves measurement devices, some hand held and others with a fixed scanning region. Lasers sound common with this equipment.

    But no mention of using multiple pics to build a 3D shape.

    QUESTION #1: What is the proper terminology to refer to "building a 3D shape with multiple pictures?" I'm guess it is not "scanning."

    QUESTION #2: To get help with this method, what forum/subforum should I go to?

    QUESTION #3: What are recommended products? Obviously, keeping costs to an absolute minimum are a constraint.

    Thanks in advance,
    Tom

  2. #2
    Staff Engineer LambdaFF's Avatar
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    You should try the 123D Catch thing : it is free. However, please note that hollow shapes are not easy to do though.

  3. #3
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    Photogrammetry is the word you're after.

    The software of the moment is called "Capturing reality" and is in BETA and free only until the end of the month. The old standard was Agisoft.

    All you have to do is take lots (more than you think you would need from all angles) of photographs around an object. Load them into the software and assuming the lighting/angles are OK, it will align and combine them into a point cloud/mesh. You'll probably have to do some scaling to get the sizing correct. Whether you'll get your tolerances I'm really not sure.

    There's a good usergroup on facebook called "3D Scanning User Group" - where most people use cameras.

  4. #4
    Super Moderator curious aardvark's Avatar
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    you best bet is to ignore scanning and just make it in openscad. Which is designed to work by building up basic shapes into a final model.

    Put it this way - a week with openscad and you'll have a parametric model that works.

    A month with photo based 'scanning' and you'll have a patchy model, the wrong size with lots and lots of post processing to do before you get anywhere close to a printable object.
    You will also have to learn how to use a number of very different pieces of software - rather than one easy to learn modeller.

    So despite the tile of this thread - yeah you do need cad :-)
    Because even if you manage to get a photo generated model - you'll neeed to learn a cad package or three to tidy it up, hollow it out, make any bolt holes etc.

    Whereas a short openscad script will generate it all in a convenient ready-to-print and easily alterable model.

    have a look at this tutorial: http://edutechwiki.unige.ch/en/OpenS...l#Introduction

    It really is as easy as measuring things and then saying what shape you want and where you want it :-)

    This probably a better starter tutorial: https://peak5390.wordpress.com/2013/...enscad-basics/

    The thing about openscad that really appeals to me is that no drawing is necessary and with a few basic commands it's surprising just how complex a model you can produce.
    Last edited by curious aardvark; 01-28-2016 at 07:57 AM.

  5. #5
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    An intake manifold is unlikely to be a simple thing to measure (the ports especially.)

    Yes they would need to use CAD after, but using 3D Scanning is a very beneficial tool to use as a template to model around. As long as the scanning method is up to par, you'll get a much better result quicker.


    Post some pictures MrCreosote if possible

  6. #6
    Super Moderator curious aardvark's Avatar
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    I was going by this statement:
    The parts are simple. Cylindrers, orthogonal blocks, perpendicular holes, etc. where an accuracy of 1/8" would be fine. 3/16" possibly acceptable, and 1/4" excessive.

  7. #7
    UPDATE:

    Finally back into this but to help a friend make a copy of a tail light lens.

    Friend was going this way MeshRoom > AutoDesk Fusion 360 > MeshMixer/Cura?Blender

    I found

    Tried 123D Catch - DISCONTINUED
    Tried AutoDesk ReMake - DISCONTINUED
    Tried AutoDesk ReCap - No Hobby License
    ... (!)

    Problems seem that Fusion only allows 50k triangles and requires manual conversion from triangles to quads (which makes no sense to me - I'm not up to speed yet.)

    QUESTION 1: Is this a good selection of software?

    NOTE: I am a senior ProEngineer AutoMesh / NASTRAN FEM jock, so I know all that stuff.

  8. #8
    Super Moderator curious aardvark's Avatar
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    you still trying toi get a scan from something costing less than $3000.
    I admire your optimism :-)

    MeshRoom > AutoDesk Fusion 360 > MeshMixer/Cura?Blender

    can't you just do it in fusion 360 ? Not sure why you'd need meshroom or meshmixer.
    You should be able to export an accurate .stl file direct from fusion360. Otherwise what's the point of it ?
    Just looks like it's overcomplicated.

    And i still stick by digital calipers and openscad ;-)

  9. #9
    We already did digital calipers, rulers, protractors, tracings, templates, etc. to measure, on site, the induction system or a historic prototype engine and the results very disappointing. Not being able to have the parts in a machine shop with proper equipment is a serious limitation. Not having a Bridgeport w/XY readout is a PITA for hole position measurement.

    Back to where we're at:

    Method is: Meshroom(photogam) > MeshMixer (CAD edit/fix mesh) > Cura (slicer) > Print part

    I don't think Fushion will photogam - AutoDesk has ReCap Pro for that (with no hobby license of course).

    Keep in mind I didn't come up with these choices or procedures.

    Photogam resolutions range from blurry to sharp for the various 'wares out there. Still surveying comparisons for best pic keeping in mind the First Rule of Buying Technology: Only buy what you need because 6 months later, what you bough is obsolete and inferior. So for now, it's free open source until we need more.

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