Importing 3D point coordinates

jaschaaa

Hi all,

I am new to Onshape and I am starting to like it. I have something I have difficulties with though: importing 3D (point) data to use as a basis for building a propeller blade model.

External software (Octave) calculates the point coordinates of radial blade sections. If the sections where planar, I think I could easily get away by using dxf as an intermediate file. In this case however, my data is three dimensional and the dxf import only seems to like 2D files. 

The next problem I may run into is how to create splines through my 3d points. Once I have the splines, I expect I can easily loft the surfaces together to a blade. 

I you the community can give me some advice. Other approaches to get it done are also welcome of course! 

ilya_baran

The default interpretation is actually meters, not inches.

Here's what I was able to do with your example after splitting the data in half (I'm assuming a sharp edge of the blade is desirable) -- don't know if the accuracy is good enough: https://cad.onshape.com/documents/577ae587e4b03be38b73ba65

ilya_baran

This type of thing cannot currently be done with the Onshape UI, but it be done with FeatureScript -- start with the 3D spline example linked from here: https://www.onshape.com/featurescript
You can copy/paste 3D points from Octave as an array of arrays [ [x1, y1, z1], [x2, y2, z2], ... ] and use a processed version of that instead of the selection points in the 3D spline feature.  Post here as you run into issues and we'll help.

jaschaaa

ilya_baran said:

This type of thing cannot currently be done with the Onshape UI, but it be done with FeatureScript -- start with the 3D spline example linked from here: https://www.onshape.com/featurescript
You can copy/paste 3D points from Octave as an array of arrays [ [x1, y1, z1], [x2, y2, z2], ... ] and use a processed version of that instead of the selection points in the 3D spline feature.  Post here as you run into issues and we'll help.

Hi Ilya,

Thanks for the hints! Following your advice I was able to draw some 3D splines from external data. 

Now I am stuck again: 
I have several radial blade sections drawn by the 3D splines. Now I want to combine them to a solid blade using the loft command (in the part studio). Somehow I can't select the splines when using the loft command. 

Any advice?

ilya_baran

Are you able to do it with a surface loft?

jaschaaa

Surface loft works. Solid still does not, although I have closed curves.

Another silly question: how do I tell the program this is in mm units? It now seems to assume inches...

Here is a code example:

FeatureScript 336;

import(path : "onshape/std/geometry.fs", version : "336.0");

const data1=[[29.121,7.2093,-19.415],[29.12,7.2119,-19.294],[29.119,7.2188,-18.933],[29.116,7.2272,-18.336],[29.115,7.233,-17.512],[29.116,7.2306,-16.47],[29.12,7.2141,-15.224],[29.129,7.1773,-13.789],[29.144,7.1139,-12.183],[29.168,7.0183,-10.424],[29.199,6.8852,-8.5345],[29.24,6.7095,-6.5368],[29.29,6.4867,-4.455],[29.35,6.2121,-2.3143],[29.418,5.881,-0.14117],[29.494,5.4885,2.0373],[29.575,5.03,4.1936],[29.66,4.5007,6.3016],[29.747,3.8868,8.3498],[29.83,3.1913,10.292],[29.903,2.4162,12.103],[29.959,1.5667,13.759],[29.993,0.6517,15.24],[29.998,-0.31668,16.53],[29.971,-1.3232,17.613],[29.908,-2.3507,18.481],[29.809,-3.3807,19.125],[29.676,-4.3957,19.541],[29.514,-5.3797,19.728],[29.327,-6.3204,19.686],[29.121,-7.2093,19.415],[29.121,-7.2093,19.415],[28.912,-8.0044,18.935],[28.721,-8.6667,18.268],[28.556,-9.1944,17.422],[28.428,-9.5845,16.407],[28.343,-9.8337,15.236],[28.306,-9.9386,13.923],[28.321,-9.8968,12.483],[28.386,-9.7076,10.933],[28.498,-9.3725,9.2871],[28.651,-8.8961,7.5622],[28.833,-8.286,5.7732],[29.034,-7.5531,3.935],[29.24,-6.7114,2.0628],[29.44,-5.7681,0.15458],[29.622,-4.7446,-1.7542],[29.776,-3.6615,-3.6452],[29.892,-2.54,-5.5012],[29.967,-1.4014,-7.3052],[29.999,-0.26617,-9.0398],[29.988,0.84568,-10.688],[29.939,1.9154,-12.234],[29.857,2.9255,-13.661],[29.751,3.8596,-14.956],[29.629,4.7027,-16.104],[29.502,5.4412,-17.096],[29.381,6.0631,-17.92],[29.274,6.5581,-18.569],[29.192,6.9178,-19.038],[29.139,7.1361,-19.32],[29.121,7.2093,-19.415]];

const data3=[[43.983,11.865,-21.08],[43.988,11.847,-20.94],[44.003,11.79,-20.522],[44.029,11.693,-19.831],[44.066,11.552,-18.877],[44.116,11.363,-17.674],[44.177,11.12,-16.238],[44.252,10.82,-14.587],[44.339,10.458,-12.744],[44.438,10.03,-10.73],[44.547,9.5338,-8.573],[44.664,8.9678,-6.2987],[44.787,8.3304,-3.9361],[44.914,7.6208,-1.5153],[45.039,6.838,0.93255],[45.161,5.9817,3.3751],[45.275,5.0516,5.7798],[45.375,4.0471,8.1156],[45.46,2.9551,10.367],[45.52,1.7881,12.481],[45.552,0.55396,14.429],[45.55,-0.73602,16.184],[45.509,-2.0673,17.726],[45.427,-3.4222,19.036],[45.304,-4.7804,20.101],[45.143,-6.1203,20.913],[44.947,-7.4203,21.465],[44.725,-8.6601,21.757],[44.484,-9.8222,21.789],[44.234,-10.893,21.562],[43.983,-11.865,21.08],[43.983,-11.865,21.08],[43.751,-12.694,20.374],[43.559,-13.339,19.476],[43.415,-13.799,18.396],[43.328,-14.072,17.148],[43.3,-14.155,15.746],[43.336,-14.046,14.209],[43.433,-13.744,12.554],[43.586,-13.249,10.799],[43.788,-12.565,8.964],[44.027,-11.701,7.064],[44.289,-10.667,5.1152],[44.559,-9.4787,3.1324],[44.819,-8.1566,1.13],[45.059,-6.7091,-0.89577],[45.261,-5.1681,-2.9083],[45.416,-3.5619,-4.8902],[45.515,-1.9189,-6.8256],[45.555,-0.26727,-8.6983],[45.535,1.3655,-10.492],[45.46,2.9533,-12.19],[45.336,4.4713,-13.777],[45.172,5.8968,-15.239],[44.982,7.2087,-16.56],[44.777,8.3876,-17.729],[44.572,9.4165,-18.736],[44.38,10.28,-19.571],[44.216,10.966,-20.227],[44.09,11.463,-20.7],[44.01,11.764,-20.985],[43.983,11.865,-21.08]];

const data5=[[58.881,16.359,-21.679],[58.892,16.318,-21.526],[58.926,16.194,-21.069],[58.983,15.985,-20.314],[59.063,15.689,-19.274],[59.164,15.303,-17.963],[59.286,14.822,-16.4],[59.428,14.245,-14.607],[59.586,13.57,-12.608],[59.757,12.795,-10.431],[59.937,11.922,-8.1036],[60.122,10.951,-5.6564],[60.306,9.8869,-3.1214],[60.484,8.7317,-0.53242],[60.65,7.4897,2.0758],[60.799,6.1653,4.6672],[60.925,4.7636,7.2056],[61.023,3.2891,9.6562],[61.087,1.7298,12],[61.111,0.10845,14.179],[61.091,-1.5613,16.163],[61.024,-3.2627,17.925],[60.908,-4.9759,19.442],[60.745,-6.6786,20.697],[60.538,-8.3465,21.678],[60.295,-9.9547,22.379],[60.023,-11.479,22.796],[59.735,-12.898,22.931],[59.44,-14.192,22.787],[59.152,-15.349,22.368],[58.881,-16.359,21.679],[58.881,-16.359,21.679],[58.647,-17.179,20.762],[58.471,-17.768,19.66],[58.361,-18.125,18.384],[58.322,-18.25,16.95],[58.356,-18.141,15.374],[58.462,-17.797,13.678],[58.635,-17.218,11.882],[58.867,-16.408,10.005],[59.146,-15.374,8.0673],[59.456,-14.125,6.0854],[59.782,-12.678,4.0747],[60.103,-11.053,2.049],[60.403,-9.2739,0.020948],[60.667,-7.351,-2.0151],[60.879,-5.326,-4.0232],[61.026,-3.2336,-5.9882],[61.101,-1.1083,-7.8965],[61.103,1.0156,-9.734],[61.032,3.105,-11.486],[60.896,5.1283,-13.139],[60.702,7.0557,-14.678],[60.465,8.8599,-16.089],[60.2,10.516,-17.362],[59.921,12,-18.484],[59.648,13.292,-19.448],[59.396,14.375,-20.244],[59.182,15.234,-20.87],[59.018,15.856,-21.319],[58.916,16.233,-21.589],[58.881,16.359,-21.679]];

annotation { "Feature Type Name" : "Jspline" }

export const Jspline = defineFeature(function(context is Context, id is Id, definition is map)

    precondition

    {

    }

    {

        const spline_id1 = id+'spline1';

        const spline_id2 = id+'spline2';

        const spline_id3 = id+'spline3';

        

        opFitSpline(context,spline_id1, { "points" : data1 });

        opFitSpline(context,spline_id2, { "points" : data3 });

        opFitSpline(context,spline_id3, { "points" : data5 });

    });

ilya_baran

The default interpretation is actually meters, not inches.

Here's what I was able to do with your example after splitting the data in half (I'm assuming a sharp edge of the blade is desirable) -- don't know if the accuracy is good enough: https://cad.onshape.com/documents/577ae587e4b03be38b73ba65

jaschaaa

Thanks a lot! Just what I needed.