Using Librecad to analize bike geometry

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Using Librecad to analize bike geometry

ddvindas
Hello Everyone!

im new here, and i wanted to know how can i do this.

the basic idea is using a PNG image of the bike itself, and draw some lines representing elements of the bike geometry, by example, seatube lengt, i draw i line between the center of the crank and the top of the seatube.

and after doiung that, inserting some know values in my models so that it gives me the exact lengt and values of all the lines i draw.

following with the example lets say that i drew a line to know the effective toptube length, from the center of the saddle to the top of the stem, but i dont really know what is the exact dimension of this, but since i know the dimension of the seatube, i cant use it to determine everyting else.
this can also help me find out the values of head angle, stack, reach, and all the other measurements related to bike geometry just by using an image of the bike and a know value.

i know there must be a way to do this but i couldnt figure it out by myself so i opted to ask for help here.

Thanks in advance!
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Re: Using Librecad to analize bike geometry

LordOfBikes
Administrator
Hi,

this is surely possible. A quick search showed me these threads:
https://forum.librecad.org/Can-I-define-distances-between-points-in-Librecad-2-1-3-td5719156.html#a5719159
https://forum.librecad.org/Scaling-imported-images-td5711385.html#a5711554
https://forum.librecad.org/image-reference-td5718665.html

They handle similar issues and show solutions. You may find more with forum search.

Basically import the image.
Draw a line of known length on the image.
Measure the drawn line length.
Use measured length and real world length to scale the image.

Put the image on a separate layer, that you can disable it, because there is an issue that you can't select entities which are on the image.

Armin
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Re: Using Librecad to analize bike geometry

flywire
In reply to this post by ddvindas
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Re: Using Librecad to analize bike geometry

perepujal
In reply to this post by ddvindas
Hi, in plus of what are already replied, I want to put emphasy on taking the image with the less distortion possible.
Near shots put lot of distortion, which is null at the center and high at the edges, the ideal are shots taken from as far as possible, maybe with a teleobjective
Also the bike should be perfectly perpendicular to the camera sight as possible.

Other than that, as explained in the other posts, it is just a matter of inserting the image and drawing, scaling and measuring over it.