Technic 854 Go Kart


Technic 854 Go Kart
#1
Hi there,

this is my third OMR-model: 854 Go Kart of 1978.

Known issues:
- The hoses are not symmetrical.
- The steering universal joint does not fit exactly.
- The sticker "9" across multiple bricks is missing.

Thank you Philippe and Johann for the feedback to my other two models - I hope this file is nearly OMR compliant already.

Any feedback is welcome, thank you very much. Smile

Edit: changed wheel color from brick-black to rubber-black as suggested for the 8845 by Philippe.

Regards
Stefan


Attached Files Thumbnail(s)
   

.mpd   854-1 - Go Kart.mpd (Size: 658.21 KB / Downloads: 11)
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RE: Technic 854 Go Kart
#2
Fixed hoses and added sticker, so only steering universal joint remains as issue.


Attached Files
.gif   854-1 - Go Kart.gif (Size: 48.87 KB / Downloads: 117)
.mpd   854-1 - Go Kart.mpd (Size: 43.23 KB / Downloads: 9)
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RE: Technic 854 Go Kart
#3
(2020-02-24, 18:24)Stefan Frenz Wrote: Fixed hoses and added sticker, so only steering universal joint remains as issue.

   

.mpd   854-1 - Go Kart v2.mpd (Size: 43.26 KB / Downloads: 9)

Proposed steering universal joint soluce (solved with geogebra)  Big Grin
Remains issues easy to solve : Gap between rear wheels, main position of the model (front and rear wheel not at the same level, front rear not on the floor at rendering)
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RE: Technic 854 Go Kart
#4
(2020-02-24, 18:24)Stefan Frenz Wrote: Fixed hoses and added sticker, so only steering universal joint remains as issue.

I wonder why the sticker appears transparent in that image, when it's not actually?

And does LDCad's universal joint helper tool do any good for the steering joint? (I didn't spot the issue myself, but I didn't look terribly closely.)
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RE: Technic 854 Go Kart
#5
(2020-03-04, 0:08)N. W. Perry Wrote: I wonder why the sticker appears transparent in that image, when it's not actually?

I think that's a rendering artifact. Based on how LDView works (even though I think this picture came from LDCad), I know that edge lines need to be pulled toward the camera when they are drawn, or they won't show up properly. I suspect that the edge lines have been pulled forward a little too much, and it is causing them to bleed through the opaque sticker.
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RE: Technic 854 Go Kart
#6
(2020-03-04, 2:15)Travis Cobbs Wrote: I think that's a rendering artifact.
Me too - the lines sometimes show up and sometimes don't depending on camera angle and zoom. But I have done only few stickers, and this one is the first with non-rectangular outline. Perhaps I did something wrong while following the howto...?
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RE: Technic 854 Go Kart
#7
(2020-03-03, 21:56)Marc Giraudet Wrote: Proposed steering universal joint soluce (solved with geogebra)  Big Grin
Remains issues easy to solve : Gap between rear wheels, main position of the model (front and rear wheel not at the same level, front rear not on the floor at rendering)
Hi Marc,

thanks for your feedback and the proposal. In the real model there is some tolerance, and I didn't know where to "play" it... The angles for the model were constructed with QCad. Wink
The rear wheel gaps are removed now, and yes, the front wheels are not on the same level as the rear wheels. Hum, I just like the main parts being not inclined, so would it be preferred to rotate the main model in the only step of the main sub file? There are always rounding errors I really dislike...

Best regards
Stefan
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RE: Technic 854 Go Kart
#8
(2020-03-04, 7:48)Stefan Frenz Wrote: The rear wheel gaps are removed now, and yes, the front wheels are not on the same level as the rear wheels. Hum, I just like the main parts being not inclined, so would it be preferred to rotate the main model in the only step of the main sub file? There are always rounding errors I really dislike...
When the whole model is tilted, I put it untilted in a submodel, and tilt that submodel in main model.
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RE: Technic 854 Go Kart
#9
(2020-03-04, 2:15)Travis Cobbs Wrote: I think that's a rendering artifact. Based on how LDView works (even though I think this picture came from LDCad), I know that edge lines need to be pulled toward the camera when they are drawn, or they won't show up properly. I suspect that the edge lines have been pulled forward a little too much, and it is causing them to bleed through the opaque sticker.
Yes, it occurs whenever edge lines are "too close" of external surface. Sometimes it can even be seen on regular parts when unzoomed enough, see for example this panel preview: https://www.ldraw.org/parts/official-par...rtid=62531
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RE: Technic 854 Go Kart
#10
(2020-03-04, 12:16)Philippe Hurbain Wrote: When the whole model is tilted, I put it untilted in a submodel, and tilt that submodel in main model.
Thank you, done. Smile  

Additionally I rotated the steering axle some more (~1.923077°), so the Universal Joint is ok and the tolerance is taken between axle and 1x2 brick.


Attached Files
.mpd   854-1 - Go Kart.mpd (Size: 43.27 KB / Downloads: 6)
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RE: Technic 854 Go Kart
#11
(2020-03-04, 2:15)Travis Cobbs Wrote: (even though I think this picture came from LDCad)

Well, now I've discovered that LDCad can export PNG images. And here I've been firing up LDView every time, just to do this very thing. (Although I may continue to do so, since its "fit" command, combined with the default viewing angle, makes for a perfectly good preview image right out of the box. I'm not quite sure how to get the right default angle in LDCad.)
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RE: Technic 854 Go Kart
#12
(2020-03-04, 12:59)Philippe Hurbain Wrote: Yes, it occurs whenever edge lines are "too close" of external surface. Sometimes it can even be seen on regular parts when unzoomed enough, see for example this panel preview: https://www.ldraw.org/parts/official-par...rtid=62531

This is caused (at least in LDCad) by OpenGL's GL_POLYGON_OFFSET_FILL which pushes triangles and quads slightly back so lines are guaranteed to be on top.

LDCad currently uses glPolygonOffset(1.0, 1.0) but its effect differs per driver implementation because those parameters are only hints to the implementation.

I could make the parameters options in main.cfg if people would like to tweak them.
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RE: Technic 854 Go Kart
#13
(2020-03-04, 18:07)N. W. Perry Wrote: Well, now I've discovered that LDCad can export PNG images. And here I've been firing up LDView every time, just to do this very thing. (Although I may continue to do so, since its "fit" command, combined with the default viewing angle, makes for a perfectly good preview image right out of the box. I'm not quite sure how to get the right default angle in LDCad.)

You could use the framing preview to pose your model (same menu as the export itself).

If you always use the same rotation you could make a macro to load it.
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RE: Technic 854 Go Kart
#14
(2020-03-04, 19:34)Roland Melkert Wrote: You could use the framing preview to pose your model (same menu as the export itself).

If you always use the same rotation you could make a macro to load it.

Can I numerically enter the view rotation somehow? The only available 3D default views are 45° left and 45° right. (I use them for part bin images, so I like a nice, uniform, generic perspective view, but the 45° views aren't quite right. I guess a simple question would be, what settings did you use for the part bins of your example models?)
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RE: Technic 854 Go Kart
#15
Updated the model with official sticker 004382a, and now I'm building the B and C models.


.mpd   854-1 - Go-Kart.mpd (Size: 30.64 KB / Downloads: 1)

OMR compliant
Missing items: none
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RE: Technic 854 Go Kart
#16
thank you Smile
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RE: Technic 854 Go Kart
#17
854 Go Kart (1978) - B-Model Wheel Maintenance Machine


.mpd   854-1 - Go-Kart - Wheel Maintenance Machine.mpd (Size: 26.36 KB / Downloads: 0)
   

OMR compliant
Missing items: none
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RE: Technic 854 Go Kart
#18
854 Go Kart (1978) - C-Model Trike


.mpd   854-1 - Go-Kart - Trike.mpd (Size: 8.42 KB / Downloads: 0)
   

OMR compliant
Missing items: none
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RE: Technic 854 Go Kart
#19
Smile Thank you Smile
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