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Extending parts without 3D tools - Whammy's Warhammer IIC
Part 0 - Introduction
After building three different Shadow Cats, I've been working on another Battlemech, a Warhammer IIC (thanks to the authors: 3D model by Whammy, unfolded and released in PDO format by Shiftdel, with Sturm's "Multicam" skin). The original scale is IIRC 1/40, but I've printed it at 4 pages per sheet; due to margins, the resulting scale is not 1/80 but roughly 1/95; I estimate the finished height will be about 112mm. I want an articulated, poseable model; however, unlike the chicken-legged Shadow Cat, the humanoid Warhammer's parts penetrate each other at the shoulder and knee, therefore some paper engineering is required. I have neither the original 3D model nor Pepakura Designer, but the original shapes are simple enough (just generalized prisms) to modify using only 2D tools with, I hope, acceptable precision. My tools of choice are Inkscape (vector graphics) and GIMP (raster graphics), both on Linux. A shortcoming of this approach is that's difficult reusing the effort for other skins. At present, most structural parts are done, and I'll take some time to document my progress, with emphasis on nonstandard steps. |
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That is the downside of generic off the shelf 3D models. They really were not meant to exist in the real world under real world laws.
The key is to not only get the parts to go together or sit upon each other, but to ensure that the model will not fall over when posed. |
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Looking forward to your build since I would really like to see how you plan on making the knees jointed.
Do you also have plans for the ankles ? |
#4
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Couldn't you just scale the generic joints set that shiftdel released to make them fit with this model?
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Quote:
Wish it were so simple, but the thighs and shins overlap. The same for the arms and shoulders. |
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Part 1 - The problem and the plan
In Pepakura Viewer (PV), here's the screenshot of a rear view of the right upper limb. Texture and shape suggest the "real" mech has at least 3 joints there; the hull/shoulder one is trivial, and we'll take care of the arm/gunpod one later; let's work on the short arm, which swings as shown by the green arrow: It's trivial cutting the black hole under the shoulder part: However, the arm's upper end must be extended and articulated inside the shoulder: Assuming the extended end can be straight, let's draft how it could look like. I provisionally chamfered two edges, which could otherwise constrain the rotation angle; we'll see later if that's enough: How much longer must the arm be? I set PV to use the longest possible angle of view (which is not even close to orthographic), align as much as possible a rear view, and take another screenshot. Using Inkscape, I draft upon the screenshot an outline (green) of the arm, plus some auxiliary lines (e.g., the thick red circles mark the edges of the hole cut off the shoulder). Ignoring what appears to be a round handle in the texture, I play around looking for an adequate center of rotation: too near the hole, there won't be enough space to securely anchor the rotation axle; too far, the maximum rotation angle will be too narrow to justify the effort) and consequently the arm's extra length. After that, I can draw a definitive outline; we can see a symmetric 3-sided chamfer provides enough clearance, unless I exaggerate the shoulder back's reinforcement. |
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What format are the 3d files in before you import them to Pepakura? You might be able to use an open source software like Blender to change the 3d model, would be much easier and more accurate way to visualize the changes needed, from my pov anyway as a 3d modeler.
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Quote:
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#9
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ah i misunderstood that, sorry.
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#10
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Part 2 - 2D "modeling"
Now the real work begins, and I need an unfolded arm to play with. PDFCreator (PDFC) is a virtual printer for Windows; it can capture Pepakura Viewer (PV)'s output and save it as PDF, which I can load into Inkscape for Linux. Raster editors like the GIMP can import PDFs as well, but if PV is configured to print lines as "sharp" (vector), a vector tool like Inkscape can handle the black lines separately from the textures. This opens up interesting possibilities like
Here, loaded into Inkscape, is the section of the PDF relevant to the left arm. I rotated it to ease future alignment. This is a separate layer to where I moved the original vector lines, used only as reference and back-up. I cloned it as yet another layer, where the actual work will be done. Scaling up measurements form the schematic screenshot, I extended the upper end. I also created new tabs and moved the old ones to optimize gluing, accounting for reinforcement layers. Now a copy of the original "multicam" JPEG can be loaded as yet another Inkscape layer. After pasting, scaling, rotating and flipping, I get texture patches approximately aligned with the base skin layer. Notice:
I believe the hubcap problem, visible all over the model, is caused by Pepakura wrapping textures nonconformally over arbitrary faces. It is particularly annoying in obviously square or circular features like rivets and screwheads. Finally, here's the completed left arm, with alignment marks for female joint orifices. Due to symmetry, the right counterpart is just a flip away. You might have noticed white hairline seams between the texture tiles. I don't know where's the problem, but a quick solution is duplicating the texture elements, adding a blur, moving to the background and clipping as usual. |
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