Pepakura tutorial

Discussion in 'Tutorials' started by Wolfinlied, Feb 18, 2007.

  1. Thanks Gearz

    Your reponse when I pointed out the Cellistia and Orbiter meshes to you gave me great pleasure. If you do tutorials in that style I think many would be inspired. If you write from a true heart you should not worry about literacy skill.

    This forum is home to many true hearts. Their love for this hobby/art shines through - they obviously aren't in it for fame or fortune:roll:
  2. Wolfinlied

    Wolfinlied Member

    Damnit plastic bonzai.. now i want a paper craft bonzai.. at least it wouldnt take me 10 years to grow and i wouldnt kill it. *sigh*
  3. wunwinglow

    wunwinglow Active Member


    Ref bitmaps, I really am the wrong person to advise, I avoid them if I possibly can and stick to vector format work; I use Rhino, pepakura and coreldraw exclusively, and now maybe SketchUp, so I can't give any sensible advise on this issue. Any 'painters' out there that can help?

    Ref output from Sketchup, it is essentiallly a mesh, so is 'vector' data rather than bitmap pixels. If you then bring that data into a paint program as pixels, you are right, there will be some 'adjustment' , or anti-aliasing, going on where things don't quite match. You can clean that up of course, but then your lines will move about as they get shifted to the nearest whole pixel. If the resolution is fine enough this might not matter, but you would have to check it.

    I'm only going from basic principles here, I don't have any direct experience of this, either working or being a problem, so I hope someone else can chime in with more knowledge on the subject!

  4. Wolfinlied

    Wolfinlied Member

    im pretty sure as with photoshop it rounds it to the nearest pixel, dont take my word on it though as im not 100% sure. I do alot of work with photoshop and such but mine is just painting/drawing with my wacom.. nothing quite like this.
  5. sjsquirrel

    sjsquirrel Member

    Vector vs. Bitmap

    Art Decko,

    I'll try and clear this up. In a nutshell, what you say above is absolutely correct. You create a texture as a bitmap, then "map" that texture to a 3D shape. It's not a question of "suppose" you do, this is the way you must do it.

    3D programs like Sketchup and Metasequoia represent an object(s) internally as a collection of points, lines and shapes. These points, lines and shapes define the locations and the boundaries of the surfaces that make up the 3D object. The program has no knowledge of what the surface actually looks like, just where and what shape it is. Texturing is the mechanism that we use to tell the 3D program what the surface looks like. We take a bitmap (which could be a digital photo, drawing, texture, whatever) and "map it" onto the surface. Think here in terms of trying to wrap a gift. Take an arbitrary 3D shape, and try to wrap it in wrapping paper. It's real easy with a box, but with complex shapes like an airplane, or a bulldozer it's gets tougher. The 2D texture tends to distort as it gets wrapped onto the 3D shape. And if your piece of wrapping paper (texture) isn't quite the right size, you have to make adjustments during the wrapping process (you'll see this mapping process referred to as U/V mapping, and there are others too).

    Now, so far we have a description of the 3D object, in a specific programs own unique "internal" representation. We still can't even see the thing. We've told our 3D program what shape the thing is (where the surfaces are), and we've given it a texture (what the surfaces look like). Now, to display the object on your screen, or print it to your printer, this internal representation must be converted to a suitable form. Your screen/printer displays/prints the image as line after line of pixels (usually called dots on a printer), each pixel being a certain specific color. This is, by definition, a bitmap.

    If the "vector" representation of a door (to use your example) indicates that the surface of the door should be 80.4 pixels wide, it must be rounded up or down to a full pixel - either 80 or 81 in this case. If the 3D program decides to go with 80, and your texture is 81 pixels, the result may not look as expected.

    Typically, the 3D modelling is done with a modeling program like Sketchup, Blender or Metasequoia, and the textures are done using a paint program like MS Paint, Paintshop, etc. Paint programs operate in much the same manner as your screen/printer - they see row after row of individual pixels. As Wunwinglow points out, there are other programs (like Coreldraw) that function differently. They store information about the texture image as vector data - essentially 2D lines and shapes, that are filled with colors and/or patterns.

    The benefit of vector graphics is that as you scale it up, the program actually redraws the lines, shapes, colors and patterns in the new scale, giving you more and more precise lines and shapes as you increase the scale. Bitmap based programs on the other hand start with a fixed bitmap. They have no information about what is being represented, so to enlarge an image all they can do is duplicate each pixel multiple times, and maybe make some guesses about how adjacent pixels might blend more naturally. But, the bigger you go, the grainier, and uglier it gets. Vector based programs however, store a description of what is to be represented, and can thus present it fully and completely at any scale.

    Now, here's the tricky part. Let's say you start out to develop a 1/72 scale model of a certain vehicle. You develop your 3D model, develop some textures, map the textures onto the model, and then run it through another program to unfold it into a 2D pattern, and presto, you have your model. At some point in this process you have to save your textures to a bitmap file. This may be in Jpeg, GIF, or BMP format, but a bitmap is a bitmap, and the resolution is now fixed. Once a bitmap, always a bitmap. Your final model pattern is also a bitmap. It may be wrapped in a PDF file, or saved in a JPEG file, but it's still a bitmap.

    Now, let's say you decide to produce a larger, 1/33 scale model. If you take your final pattern (which is now a bitmap) and simply enlarge it, you are up against the limitations of enlarging bitmaps as described above. If you double the scale of the 3D model, your bitmap now has to cover at least twice as much area, which it wasn't designed to do, and the 3D program simply does the bitmap enlargement for you, and you end up with much the same result.

    If however, your texture is developed in a vector based program, you open up your original vector based file, increase the scale, and then save a new, larger bitmap that is suited to the new, larger model, with absolutely no loss of quality. Unfortunately, you have to now open up your 3D model and reapply the texture and adjust the mapping.

    Even more tricky: If you think ahead, and make a high-resolution bitmap texture for your 1/72 model, planning ahead for a 1/33 model, you can go ahead and use the same texture file for both, and the 3D programs will take care of it for you, and what program you use to create the bitmap is six of one, half a dozen of the other.

    Relating this to file formats

    To extend this lesson a little further, since we're already almost there, the internal representation used by any given program (like Sketchup) can be thought of as it's native graphic file format. Take an object like a bicycle. Metasequoia has it's own, unique way of internally storing information about the shapes that make up the bicycle. Orbiter (a popular video game) uses a different internal representation for the same shapes, and Sketchup yet another internal representation. They are all describing the same object (a bicycle), and must all store the same basic information (lines, shapes, positions, colors, textures etc.), they just each have their own unique way of doing that. When you save the model to disk, each program typically uses it's own native format for saving the information. Most 3D programs support several common file formats, but none support all of them.

    This is where translation (or conversion) programs like UMC2 or 3D Exploration come in. They have been built to understand many different file formats, from many other programs/sources, and can convert from one to the other with little or no loss of information. So, you can (almost) always use your favourite program, because there's (almost) always lot's of other people out there that have the same favourite program, and one of them has probably written a program to convert that other format to the format you need. And they (or somebody else) has probably written the program to convert it back again too.

    I'm a firm believer that there's really no "best" program for anything. It's a question of what fit's your budget, does the program fit the way you think and work, and so on. Try out the popular ones, find the one you like best, then learn it inside and out. Read everything you can. Play with it. Become an expert with it.

    And have fun,

  6. catalin

    catalin Member

    my advice would be for you to use pepakura 2. it's a lot better than first version of pepakura, and makes very good unfolds, even if the 3d model has some mistakes. the interface seems to me to be more friendly, and you cand join/disjoint elements very easy, there are no bugs.

  7. Lex

    Lex Dollmaker

    I think we really need a tutorial on making/mapping textures. A lot of people is seeming to have trouble with that.
  8. sjsquirrel

    sjsquirrel Member

    Care to take the job?

    Would you like to volunteer?

    There are some out there already, some mentioned earlier in this thread if I recall correctly.

    Anyone working with a specific 3D modelling program needs to learn the mapping process for that program. For Metasequoia there's good stuff in the documentation. See

    I'll add this to my list for when I start my tutorial project. I'm trying to find out how to implement the sticky post idea but haven't had much time. Stay tuned.
  9. Art Decko

    Art Decko Member

    A very sincere "thank you" to everyone for sharing their expertise and advice.

    And sjsquirrel, I think I should send you a coupon for a finger tendon massage after that explanation! That was very comprehensive, and should be part of the site's advice archive.

    Very useful unformation, thanks again to all!
  10. keith

    keith Member

    Yes, you will get weird aliasing errors, suppose you do vertical wood slats for the door and you make them all the same size, the output from pepakura will usually make the wood slats to slightly different sizes because it 'HAS' to re-render the bitmap. It's really only noticable on small bitmap textures though.

    There are 3 ways to overcome this :-
    1. make bigger textures. (best practice)
    2. post-edit your final pepakura image.
    3. ignore them, will anyone notice?

    If you take a really, really look closely at any output from pepakura you will always find these small errors, but once you've printed the images, cut them out and glued them together, you won't notice them.

    For those that don't know how to make a texture in said metasequoia :-

    steve - meta tutorials and resource sticky are great idea's, there are a few threads you could point to as well, which show different software.
    I can provide some unfinnished meta models (and in other formats) for people to play with, finish, publish if that's any help?

    (trying to find time to do nothing)
  11. Lex

    Lex Dollmaker

    I think texturing is the hardest bit of design a novice will find. I'm still struggling sometime but when I get the hang of it I'll difinitely write a tutorial.

  12. catalin

    catalin Member

    texturing for zmodeler? does anyone know something about this? :-D
  13. sjsquirrel

    sjsquirrel Member

    It has begun

    I have talked to the list admins, created the resource thread, and gotten it made sticky. The thread is here

    Please visit the thread and start posting your recommendations. Over the next few weeks I'll work at collecting stuff and updating the sticky post.

    Keith, please send me a private message and let me know what models you have we might use as a base for a tutorial. If you PM me then I won't lose you reply. It would be great to start with something and then build from there.

    Bye for now.
  14. keith

    keith Member

    hmmmm....can't seem to PM you, or anyone!!!
    Is it my end or the forum?

    I'll try and compile a zip file with some models and upload them so you can go get them and see if they are useful in any way.

    catalin - have you tried the zmodeller website, there is a tutorial there for applying textures. It's also one of the best explainations of what a texture is that i have come across.
  15. Art Decko

    Art Decko Member

    I absolutely agree, and I think the reason is that it uses a very different set of tools and skills than designing a model.

    Designing a model is an exercise in engineering, designing textures is much more of an artistic task. I think most model designers think more like engineers than artists. The predictable result is lots of models with highly accurate and intricate designs, but primitive coloring-book style graphics.

    In my opinion texture design is just as important as model design, yet many designers treat it with far less attention or seriousness that they give model design.
  16. charliec

    charliec Active Member

    Perhaps some designers neglect graphic design but this is changing in the commercial models quite rapidly. I can only speak about AFV models but the most recent offerings by GPM have been graphically superb - Halinski has been good for some years. In part I think it's designers slowly coming to grips with the software tools to create good graphic designs. Remember it's only been in the last few years that CAD products have been used for cardmodels.


  17. PapaBear

    PapaBear Member

    I'm not sure what I can do or say to help as I mostly use Maya;
    anyone else use Maya? But if I can contribute lemme know.
    I am myself currently designing a model series with it,
    maybe a CG model build thread?

    I want to learn Rhino myself as I think the unfold is kewl.

  18. Art Decko

    Art Decko Member

    Thanks, Charlie, that's good news! I think you must be right, here at this site I have seen many military models with absolutely awesome graphics. Maybe military models lead in this regard because they are the most popular or most commercialized?

    I see your point, but on the other hand, pc graphics are now about 15-20 years old, you don't need Photoshop for that! Great graphics were already possible in the EGA (16 colors) era. To me it seems more a matter of lack of attention or priority than a matter of insufficient tools or technology.

    I see exactly the same thing in other spheres. For example, in the virtual railroading world of Trainz, people will spend countless hours making incredibly detailed 3D rail cars, then wrapping them in simple coloring-book style graphics using lurid cartoon colors. To me this negates much of the detailed design work, because the final visual impression is so unrealistic.

    It seems to me that there is a common attitude that the goal of scale modeling is to produce miniatures that in terms of physical shape and dimensions are exact scale replicas of the subject, and everything else is secondary to that.

    To my thinking, that seems short-sighted. I would say that overall visual impression is more important than exact physical shape reproduction. After all, what are we going to use a model for? To appreciate visually, isn't that the goal? Accurate physical shape will only get you part of the way to that goal, good graphics are an essential part of the formula.

    That's my opinon, anyway. I hope before the year is out you can look at my little team's designs and judge for yourself. :)
  19. keith

    keith Member

    I think the texture problem doesn't come down to just software, skill or attitude, great textures can't be made without a full understanding of the subject matter.
    I couldn't draw 3D pencil sketches very well until i started using 3D cad, i have learnt to visualize in 3D. The same goes for textures, unless you know what rust looks like you can't draw it, so you have to study it or pictures of it.
    The side of a rail car is a great example, i can't visualize it more than saying it's got colour and lines and maybe some letters, until i go and look at one (or download images of one) i have no understanding of what the weathering, rust and bird muck has done to my simplistic visualization.

    Maybe we just need some links to good weathering tutorials, texture libraries and image libraries.

    I couldn't texture very well until i found what layers were for. :-D
  20. Art Decko

    Art Decko Member

    Keith, I think you nailed it.

    To make good-looking graphics, you really need to know a little about the nature of color, light, shadow, perspective, composition, etc. Just having a great software tool alone won't do it, anymore than having a copy of MS Word will make you a great writer. Graphics artists, photographers and the like spend years studying and practicing these basic principles.

    It would be great to see more graphics-oriented tutorials explaining the basics of color, light and shadow. This kind of basic knowledge would apply to any graphics application, and could greatly benefit anyone interested in really polishing the appearance of their models.

    Yoohoo, any trained artists around :)

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