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3D Printed Bodies - HO

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  • 3D Printed Bodies - HO

    Any other 3D printer aficionados here? Would love to exchange ideas and tips on modeling cars.

    I'm working on several HO bodies using the open-source (free) 3d software called Blender.

    I have one prototype of a Cobra-like car I built just to test out the idea. It's printed in a durable, flexible synterized white nylon and fits AFX and AutoWorld chassis.

    Attached are some shots of the protytpe as printed by Shapeways. Sanded, primed and painted. I got a bit of an orange peel on the finish because the temperature was a bit cold. But after priming and sanding, the body was quite smooth.







    I have a detailed Cobra 427 almost finished that will fit a Mega-G. And a Can-Am inspired racer. Also working on replicas of my own old rides - just for nostalgic fun. A 1972 Volvo 142S, '77 Ford LTD, '88 Ford Festiva, '92 Saturn SL2, a couple of Hondas, and a Subaru Forester.

    I'll post photos as they progress.

    Best wishes for a happy new year!

    Jim

  • #2
    Jim,
    That looks great! I don't have any first hand experience with Blender or 3D printing, but after seeing your results I may be inspired to give it a try! Looking forward to seeing more.

    Mark

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    • #3
      Thanks Mark, Blender's learning curve can be a bit steep. But being open-source and FREE, there is a large community of users online with tons of great tutorials to help get anyone started. One of my favorites in getting started was "Bits of Blender" videos on youTube, made by a father/son team who had a knack for making it simple[r].

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      • #4
        Originally posted by Highwingpilot View Post
        I'm working on several HO bodies using the open-source (free) 3d software called Blender.
        I've been messing around with Blender and I was wondering whether subdivision can be used in 3D printing or not. With the smooth contours on your (awesome) car, I'm guessing it can.

        Did you use subdivision on that model, or did you create the geometry without subdivision?

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        • #5
          Emdiar, I find I get best results starting out with as few polygons as possible, adding vertices only where absolutely necessary to control the shape. Try to avoid Tris as much as possible... Quads are easier to work with and produce a smoother result.

          I use a subdivision modifier and employ edge creases to hold sharp lines where needed like around wheel wells, panel lines (on my newer designs), front grille opening, etc. It makes it MUCH easier to start rough and fine tune and subdivide areas later if needed. Sort of like carving. Rough out the shape first then add detail. I also model only one side of the car, and use a mirror modifier to automatically complete the other.

          I have roughed out AFX magna traction and Mega G (long) chassis in blender as templates that serve to position wheels, body mounts, and ensure body clearance. I'm working on one for Super IIIs.

          Once the outer skin is completed, I thicken it inward by about 1.25mm with a combination of modifiers and other manual techniques. Shapeways has material guidelines on their site for minimal wall thicknesses. Plus give a little extra to allow for sanding.

          When the model is exported for printing, all modifiers will be need to be applied. Depending on the format, the quads are converted to tris automatically.

          I haven't tried printing with a Makerbot (extrusion type) printer yet. But the samples I have seen are pretty crude and would take a lot of sanding or filler to clean up. Shapeways (powder type) printers yield a far better surface that cleans up well with some light sanding. I started with 200 grit. Then 400, then 600 grit polished it right up. I hit it with a 2 coats of primer with a light sanding after each. Then 2 coats of color and a clear coat.

          I got a sample from the new FormLabs printer that uses stereo lithography (laser activated resin). The surface quality is astounding. Super detail and smooth. But the printer and supplies are a bit pricey. For now, I'll stay with printing through a service like shapeways or Cubify.

          I can post some blender screenshots showing the process if you want. And you can check out the model in 360 on Shapeways under HO slot car.

          I'm curious to see how it would work to make a mold and resin casts from the printed and sanded prototype. Not sure if it would be cheaper to cast or print.

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          • #6
            Thanks for the info. I'd love to see some of your Blender screenshots!

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            • #7
              Blender screens

              Here are some blender screenshots of work in progress on some of the bodies... including the prototype that was printed and painted above.














              I figure if I put "Chitty" on a Mega G or Super III chassis with its wings out, I may be able to get it to really fly! ;-)

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              • #8
                Great stuff! Look forward to seeing other models!

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                • #9
                  I have modeled and 3D printed some dirt track cars for T-Jets and camera mounts for T-Jets and Life-Like cars. I used AutoCAD and SolidWorks to model the pieces, and used either a Makerbot 5th Gen or the Shapeways service to print the pieces.




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                  • #10
                    Originally posted by Highwingpilot View Post
                    I'm curious to see how it would work to make a mold and resin casts from the printed and sanded prototype. Not sure if it would be cheaper to cast or print.
                    This is exactly what I do for my 1:32 cars, the resin is about 10% lighter and of course it's much cheaper for a 1:32 car too. The other advantage is that once you've got the master model smooth, all the resin copies are the same.

                    The drawback is the cost of the silicone!

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                    • #11
                      I designed this 1953 Wayne Gas Pump at 1:10 scale & printed via Shapways.


                      I was at the Autodesk conference in Las Vegas this past fall and attended a session on "Project Memento" which is on Autodesk labs. What they were doing is just taking pictures using a tripod from multiple angles and then they just dump the 2D photos into Memento & instant 3D model. It cross references individual pixels to calculate the different camera positions and generates a 3D model that can be... scaled down... and 3D printed... pretty cool. Think about it, you're walking down the street and see... what ever... your childhood dream car. Get the phone out, snap a couple dozen pics and make a slot car body.


                      The 3D model needs cleanup but the interface in the software is particularly cool... sort of reminds you of Photoshop but 3D.


                      Here's my pump, done with AutoCAD 3D solids & I did the decals in AutoCAD as well:


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                      • #12
                        Just a few questions...
                        1 how hard would it be to do a fiat 500 from existing 3d models...
                        1 what does it cost per body ?

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                        • #13
                          ebonbetta, the car body I designed and printed on shapeways costs only $10.70 for an unpolished white plastic print. $15 for polished. But still needs sanding, priming, and painting either way. You can find there by searchng "HO Slot Car", and some other interesting stuff pops up as well. So cost is cheap enough. To model a fiat 500 would just take a bit of time in Blender. That would be a cool car! But I'm focused on finishing up an ultra-slim 3D Chassis design so I can build Chitty next. (progress reports have been posted to another forum).

                          DRW, that gas pump is amazing. Great job!! Are the hoses printed as well? And how did you finish it? What kind of paints have you used? I found that my primer coats took a while to dry on Shapeways White Strong Flexible material. But harden up nicely - I juts to let them dry longer.

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                          • #14
                            By the way, AutoDesk already makes a great FREE app called 123D Catch that converts a series of photos into a mesh.

                            But the results are best suited to organic objects. The meshes it creates are highly complex and don't lend themselves well to adjusting. But I made a portrait of my mom for my dad which came out beautifully. But trying to make a model of a smooth crisp car from digital photos leaves a lot to be desired. I posted a long explanation and illustration of this on [another slot car forum].

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                            • #15
                              Originally posted by Highwingpilot View Post
                              DRW, that gas pump is amazing. Great job!! Are the hoses printed as well? And how did you finish it? What kind of paints have you used? I found that my primer coats took a while to dry on Shapeways White Strong Flexible material. But harden up nicely - I juts to let them dry longer.

                              Thanks, and no, the hoses are 12G wire with the core striped out. The "glass" is .015" Lexan & the retractor cable (which works with a high tech mechanism I designed... a rubber band) is 1/32" stainless cable. The rest is either SWF or UFD.


                              It took a few iterations to get the painting process down. First, I rubbed Bondo glazing putty into the SWF, then wet sand starting with 320 to 1000, Tamiya fine primer (acrylic lacquer) & Then Tamiya TS lacquer for color & then micro mesh polishing pads to get the glossy shine. It's a lot of work but you can get a nice shine out of SWF.

                              The Tamiya TS rattle cans are dry enough to sand in 30 minutes or so too.


                              Originally posted by Highwingpilot View Post
                              By the way, AutoDesk already makes a great FREE app called 123D Catch that converts a series of photos into a mesh.

                              But the results are best suited to organic objects. The meshes it creates are highly complex and don't lend themselves well to adjusting. But I made a portrait of my mom for my dad which came out beautifully. But trying to make a model of a smooth crisp car from digital photos leaves a lot to be desired. I posted a long explanation and illustration of this on [another slot car forum].

                              Yes, the memento project has a ways to go... typical Autodesk, they'll offer a free tool... but if you want it to actually work you gotta fork over some $.


                              But there are tools for simplifying the mesh and you can convert to a solid & also has a very impressive editing tool for cleaning up all the "noise". It really reminded me of photoshop for 3D.


                              It also lends itself better to organic objects. I think because it depends on analizing the pixels & using algorithims to determine the various positions of the cameras, shiny, single color objects don't work well.


                              We use laser scanners at work for DOT surveying. We can now set the instrument up off the highway & scan the intersection in rather than stopping traffic and putting workers out in traffic. We use only a few locations and place "balls" around the site that have a very accurate and precise diameter. The instrument recognizes these balls and since they are precise in diameter, it can figure out the exact center, and based on that the post processing software can determine the location of the other scans... and it does shiny objects... but it won't come as an app on your phone.


                              But it's only a matter of time.
                              Last edited by DRW-FJ40; 01-28-2015, 09:48 PM.

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