Technic 854 Go Kart

[Stefan Frenz]

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.

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

Regards
Stefan

[Stefan Frenz]

Fixed hoses and added sticker, so only steering universal joint remains as issue.

[Marc Giraudet]

Fixed hoses and added sticker, so only steering universal joint remains as issue.

   

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

Proposed steering universal joint soluce (solved with geogebra) 
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)

[N. W. Perry]

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.)

[Travis Cobbs]

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.

[Stefan Frenz]

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...?

[Stefan Frenz]

Proposed steering universal joint soluce (solved with geogebra) 
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.
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

[Philippe Hurbain]

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.

[Philippe Hurbain]

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

[Stefan Frenz]

When the whole model is tilted, I put it untilted in a submodel, and tilt that submodel in main model.

Thank you, done.   

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.

[N. W. Perry]

(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.)

[Roland Melkert]

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.

[Roland Melkert]

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.

[N. W. Perry]

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?)

[Takeshi Takahashi]

Updated the model with official sticker 004382a, and now I'm building the B and C models.


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

OMR compliant
Missing items: none

[Stefan Frenz]

thank you

[Takeshi Takahashi]

854 Go Kart (1978) - B-Model Wheel Maintenance Machine


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

OMR compliant
Missing items: none

[Takeshi Takahashi]

854 Go Kart (1978) - C-Model Trike


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

OMR compliant
Missing items: none

[Stefan Frenz]

Thank you