3D software pluses and minuses

Discussion in 'Gallery & Designs' started by wunwinglow, Sep 6, 2006.

  1. wunwinglow

    wunwinglow Active Member

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    As Rick said, another thread for 3D progs would be appropriate. Yer tiz....

    Tim P (wunwinglow)
  2. Larry Marshall

    Larry Marshall Member

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    Great...could someone start this thread by some very basic comparisons with Rhino-type, MilkShape-type, and 3D CAD-type softwares? Simple stuff like virtues, limiitations, their base logic would be great. Or, is there are URL I can head to that would explain it to me. I don't find that the software sites explain any of this.

    Cheers --- Larry
  3. wunwinglow

    wunwinglow Active Member

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    OK Larry. For Rhino. www.rhino3d.com. It is a NURBS modeller, where the curves, surfaces and solids are generated from mathematical formulae. Don't worry, the only numbers you need to worry about are the dimensions, scale etc., the program handles all the nitty-gritty stuff. This approach is analagous to vector based 2D graphics. Changes, trims, etc happen instantly. Usually if the program slows up, it is due to mesh generation required by the rendering process, not the fundemental modelling.

    Rhino has an extensive range of tools for generating lines (called curves, even if they are straight) which will be familiar to any one used to a 2D CAD program. As with all these programs you will need to understand how 3D constructs are produced and manipulated on a 2D monitor screen. In Rhino you have the usual 4 basic views, but you can have as many, or as few as you need.

    You MUST understand how you can define points in space as these are fundamental to how you input and edit your design. Also you MUST understand how the grid is set up, how the various snap functions help (or sometimes hinder!) and you MUST appreciate that you have to work accurately.

    You MUST do the basic tutorials, and I'd recommend a gentle wander through the command list. Each command has a mini-tutorial which will illustrate how the command works. Even if you don't use it immediately, it will lodge in the back of your mind for when you might need it.

    For paper models, check out particularly the UnRollSrf command, especially the limitations on what sort of surfaces it can unroll. This limitations have a FUNDAMENTAL effect on how you design your model!

    Finally, I did a partial tutorial building a Sukhoi Su 7 jet which covered a lot of the basics in Rhino. I'm at work just now, but if anyone can locate the url for it, perhaps they will post it. I will look it up when I get home.

    Only you can justify what you can spend on your hobby. I am lucky having access to the software through my job, but I would certainly buy the program myself otherwise. Version 4 is in beta just now, and has some even more advanced features which make it even better. It is a VERY powerful program, and even compared to the Biggies in the CAD world, bang per buck ratio is huge.

    Any questions specific to Rhino, I'd be thrilled to help further; just ask!

    Tim P (wunwinglow)
  4. wunwinglow

    wunwinglow Active Member

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    OK Larry. For Rhino. www.rhino3d.com. It is a NURBS modeller, where the curves, surfaces and solids are generated from mathematical formulae. Don't worry, the only numbers you need to worry about are the dimensions, scale etc., the program handles all the nitty-gritty stuff. This approach is analagous to vector based 2D graphics. Changes, trims, etc happen instantly. Usually if the program slows up, it is due to mesh generation required by the rendering process, not the fundemental modelling.

    Rhino has an extensive range of tools for generating lines (called curves, even if they are straight) which will be familiar to any one used to a 2D CAD program. As with all these programs you will need to understand how 3D constructs are produced and manipulated on a 2D monitor screen. In Rhino you have the usual 4 basic views, but you can have as many, or as few as you need.

    You MUST understand how you can define points in space as these are fundamental to how you input and edit your design. Also you MUST understand how the grid is set up, how the various snap functions help (or sometimes hinder!) and you MUST appreciate that you have to work accurately.

    You MUST do the basic tutorials, and I'd recommend a gentle wander through the command list. Each command has a mini-tutorial which will illustrate how the command works. Even if you don't use it immediately, it will lodge in the back of your mind for when you might need it.

    For paper models, check out particularly the UnRollSrf command, especially the limitations on what sort of surfaces it can unroll. This limitations have a FUNDAMENTAL effect on how you design your model!

    Finally, I did a partial tutorial building a Sukhoi Su 7 jet which covered a lot of the basics in Rhino. I'm at work just now, but if anyone can locate the url for it, perhaps they will post it. I will look it up when I get home.

    Only you can justify what you can spend on your hobby. I am lucky having access to the software through my job, but I would certainly buy the program myself otherwise. Version 4 is in beta just now, and has some even more advanced features which make it even better. It is a VERY powerful program, and even compared to the Biggies in the CAD world, bang per buck ratio is huge.

    Any questions specific to Rhino, I'd be thrilled to help further; just ask!

    Tim P (wunwinglow)
  5. Larry Marshall

    Larry Marshall Member

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    Thanks for the description of Rhino, Tim.

    <grin>...I didn't know how math averse the human population was until I started asking about this stuff. Everyone adds these caveats to their descriptions so I assume it's a problem. I made a living as a population dynamics modeler so some simple algebra isn't a barrier. That said, I've done enough of it that not having to do any more sounds good to me :) When it comes to Rhino, the only number/math that causes me trouble is the one that reads $900.

    Now that you mention it, it's EXACTLY the same in at least one way. While there are lots of command lists and 'how to make a...' tutorials, there's absolutely NOTHING that teaches the use logic. When I was moving from pencil to 2D CAD I was trying to replace the pencil directly with vector/polyline commands. Truth is, fluency in 2D CAD comes when you figure out that you simply create drawings differently with CAD than you do when drawing with a pencil and eraser and I've yet to see any document that teaches those things. It seems the same for 3D systems.

    I once did a Rhino tutorial and was impressed with its operation.

    This is the sort of 'logic' stuff that I was talking about above.

    Ah...so Rhino does its own unfolding. No need for Pepakaru. That's neat. Let me ask you a non-model question about Rhino. How well does it work as a tool to create isometric drawings for books and articles? I ask because that may be my 'hook' into justifying its purchase :)

    That would be really good to see.

    I'm good at "justifying" purchases up to around $200 but above that things start getting harder to justify. But I confess that I've wanted Rhino (or something like it) for reasons other than card modeling so maybe...just maybe...

    Thanks again, Tim.

    Cheers --- Larry
  6. wunwinglow

    wunwinglow Active Member

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    Quick reply ref the illustration commands, make2d is the one, it generates a 3-view (1st or third angle projection) plus a perspective view of the object selected. You can elect to show hidden and tangent lines and then export the resulting images to Coreldraw, Illustrator etc. Also available is Penguin, a Rhino Plug-In which generated non-photographic renderings direct from within Rhino. These are perfect for illustration work; but it is another expense! www.penguin3d.com for details.

    Frankly, with Rhino, apart from parametric modelling, there is probably a command, or a plug-in, which will do what you want. And even then, if not, you can script your own commands and plug-ins. These can be simple one-click operations, to hydrostatic calculations for ships, to gear shapes, to rapid prototyping output, and so much more besides. As Gil says, if you want to do something with Rhino, there probably is a tool for it already!

    I should be on commission from McNeels, shouldn't I!?

    Larry, get the demo, do the tutorials, flash light, rubber duckie etc.

    Best wishes,

    Tim P (wunwinglow)

    PS Sukhoi article is at http://www.kipperboxes.co.uk/assets/Su7_Tutorial_text.html Sorry I never finished it; or the model!
  7. Larry Marshall

    Larry Marshall Member

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  8. tausugAir

    tausugAir Member

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    Sukhoi tutorial....!!!

    What gave me the ability and facility to use Rhino IS Mr. Tim Perry Sukhoi 7 tutorial.... Many, many thanks!!!....

    Muhammad
  9. SteveM

    SteveM Member

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    Nope, that is not what UnrollSurface does. Unfolding multiple surfaces is not unrolling a single surface. Unrollsurface takes a single curved surface and unrolls it to a flat surface. Select the surface of a cylinder (not the ends) and it will produce a rectangle. Select a sphere and it will fail. The surface must be a simple curve, with only a single direction of curvature. But that is good since that is how paper curves. Select a cube, and you will six squares stacked on top of each other, not an unfolded cube.
  10. keith

    keith Member

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    Larry,
    What do you mean by 'base logic'?

    do you mean is it a polygon modeller, subdivision modeller, surface modeller, displacement modeller, solid modeller?
  11. wunwinglow

    wunwinglow Active Member

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    Ref complex unfolding, Rhino v4, now in beta, will have this facility. There was a vid on the Rhino site.

    Tim P (wunwinglow)
  12. Larry Marshall

    Larry Marshall Member

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    This points out the level of my ignorance; it goes down as low as the base vocabulary. When I've read about using Pepakura to 'unfold', I thought the goal was to do what you're describing, to create an object as a flat surface. Lordy do I wish I could find a 3D for Dummies book. Thanks, Steve.

    Cheers --- Larry
  13. Larry Marshall

    Larry Marshall Member

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    I suppose that if I knew what I meant I wouldn't have asked the question. I'm just talking too dumb for you guys, I guess. What I'm looking for is some URL or book that I can read that will, for instance, define each of the approaches you've just listed and explain something of the advantages/disadvantages of each. If that were couched in terms of card modeling that would be great but not necessary.

    Cheers --- Larry
  14. wunwinglow

    wunwinglow Active Member

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    No such thing as a stupid question!

    Unfolding usually refers to taking a MESH model, breaking the 'welds' at some vertices and literally 'unfolding' the mesh so it lays flat. This is what Pepekura does.

    Unrolling refers to the sort of thing Rhino does, which takes ONE surface that is curved IN ONE DIRECTION ONLY and laying it out flat like a piece of carpet.

    Does that make sense?

    Tim P (wunwinglow)
  15. TheWebdude

    TheWebdude Just a Member

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    Unfortunately you're going to find very little on general theory and comparisons. Most available material on theory is in relation earning a degree in 3D programming and "most" all practial application material is program specific.

    Here's a few that "might" help:

    http://www.euclideanspace.com/mjbWorld/index.htm
    http://www.tutorialfind.com/tutorials/3dsoftware/3dbasics/

    You may be able to find some comparison information at the Siggraph archives but it's pretty heady stuff there:-D :

    http://www.siggraph.org/
  16. wunwinglow

    wunwinglow Active Member

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    I'd just get into the tutorials that ship with most of these programs, or are available on their respective websites. The practical hands-on approach will give you a working knowledge of how to get what YOU want, without getting too knotted up with the number crunching. After all, the whole purpose of computers is to enable you to manipulate the data, without getting swamped by the detail.

    Just do the flash light and rubber ducky! The rest will be a breeze!

    Tim P (wunwinglow)
  17. Gil

    Gil Active Member

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    Engineering Drawing Textbooks

    A useful resource to review as regards the construction of cardmodel surfaces is an Engineering Drawing textbook. The section devoted to Interesections and Developments covers the Theory of Development. Rhino performs surface development right out of the text; "the surface is composed into a plane by unfoldment". The one overriding rule in the design of cardmodels is that the media is planar in nature meaning that like sheet metal it has the limitation of being curved in only one axis out of three. How one achieves a desired shape is part of the pursuit to folded perfection whether it be sheetmetal or paper.

    -Gil
  18. keith

    keith Member

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    Larry,
    get you now. I tried writing a '3D for dummies', it's not easy, there are so many different ways of doing the same thing. I found a great basic 3D site, but it's in finnish!
    The method you described for 2D, converting from a pencil to commands is the same for 3D, you build the 3D model in the same way as you would build a real model, remembering tabs can be added later.
    3D cad software is a tool, nothing more, for designing models. My suggestion is you learn to use as many tools as needed.
    If you want rolled surfaces you can use a surface modeller like Rhino to produce the unrolled parts.
    If you want an unfolded textured box you can use metasequoia or milkshape.

    Both types of software are really good at what they do, but there's no software can do everything.

    What type of models are you designing? If you say aircraft i'll shout RHINO at you :)
  19. Larry Marshall

    Larry Marshall Member

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    And so it goes with so many things. Each world has its own language and logic and yet learning the basics of both is often the most difficult task because nobody talks about it; those involved already "know" it, or at least wouldn't be caught dead admitting that maybe they don't fully understand all the words they toss around :)

    Thanks for these. They look like they might be useful. In any case, I'm going to spend time playing with Rhino and MilkShape and see what I can learn.

    Thanks to all for tolerating my incessant questions on this.

    Cheers --- Larry
  20. Larry Marshall

    Larry Marshall Member

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    My queries have nothing to do with number-crunching. They have to do with understanding that underlying logic of 3D graphics systems and the jargon that surrounds them. I guess it's the scientist in me but I like to understand more than which button to push to make something happen. Maybe I'll get over it :)

    BTW, it seems that the Rhino training "registration" isn't working properly as I can't register to get access to their basic tutorial stuff. When I try to register they want me to enter the letters I see but rather than presenting me with some graphic letters as most systems do, they just put some ASCII text letters. If I type them they tell me I've done so incorrectly. As I can't register I also can't tell them about the problem. Catch-22!

    Cheers --- Larry