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Rotating a line around an axis with FeatureScript
aleksi_hermonen
Member Posts: 5 ✭
I am trying to make a circular slide rule, where there are tics on a circle with uneven spacing. I have done this before on TinkerCad, where I did the tic placements with GeoGebra, saved that as a picture, imported the picture to TinkerCad and made a hole object out of it. It worked and I'm happy with the end result, but now, some time later, I have gotten to know OnShape and I'm so happy that I switched. It's so much more efficient and versatile.
And now I started to think about practicing by making the same (or almost the same) desing in OnShape.
But I have a problem: The Circular Pattern tool (both in Sketch view and in default view) allows only even spacing, and the pattern on slide rule is uneven, determined by logarithmic function.
So I started to get to know FeatureScript, I knew a little java programming before, so many things were familiar already. Also the ready-made buttons in Feature Studio view were really helpful. But now I'm stuck. At this point, I am trying just to rotate a copy of a given line by given angle around given line as an axis. When I get this to work, later I can put this command inside a loop and make more rotated copies at once. I have made a single horizontal line and a perpendicular rotation axis to a sketch and I have made following simple FeatureScript code (it already felt really nice to get the precondition to work properly). You can see the whole project at here:
https://cad.onshape.com/documents/badb8f11d26945aec3ce9ef4/w/fd641e36e3eb9ad62d2080b6/e/77c1d6e463b1c58924c05949?renderMode=0&uiState=66eef47a71fa000941fa5fb8
FeatureScript 2455;
import(path : "onshape/std/common.fs", version : "2455.0");
annotation { "Feature Type Name" : "Tics", "Feature Type Description" : "" }
export const myTics = defineFeature(function(context is Context, id is Id, definition is map)
precondition
{
annotation { "Name" : "Line", "Filter" : GeometryType.LINE, "MaxNumberOfPicks" : 1 }
definition.ticLine is Query;
annotation { "Name" : "Axis", "Filter" : GeometryType.LINE, "MaxNumberOfPicks" : 1 }
definition.axis is Query;
annotation { "Name" : "step:" }
isReal(definition.step, POSITIVE_REAL_BOUNDS);
}
{
var rotation = rotationAround(definition.axis, -45 * degree);
opPattern(context, id + "pattern1", {
"entities" : definition.ticLine,
"transforms" : [rotation],
"instanceNames" : [id + "instance1"]
});
});
[end of code]
Here is an image of the earlier circular slide tule I made with TinkerCad. Tics are painted and numbers are printed with labelling machine:
Comments
rotationAround needs a Line object not a Query - use evAxis to convert.
Thank you for advice. I converted the axis to line object with evAxis command and used that on rotationAround, but unfortunately it still doesn't work. At the moment my code looks like this:
FeatureScript 2455;import(path : "onshape/std/common.fs", version : "2455.0");
annotation { "Feature Type Name" : "Tics", "Feature Type Description" : "" }export const myTics = defineFeature(function(context is Context, id is Id, definition is map)
precondition
{
annotation { "Name" : "Line", "Filter" : GeometryType.LINE, "MaxNumberOfPicks" : 1 }
definition.ticLine is Query;
annotation { "Name" : "Axis", "Filter" : GeometryType.LINE, "MaxNumberOfPicks" : 1 }
definition.axis is Query;
annotation { "Name" : "step:" }
isReal(definition.step, POSITIVE_REAL_BOUNDS);
}
{
var axisLine = evAxis(context, {"axis" : definition.axis});
var rotation = rotationAround(axisLine, -45 * degree);
opPattern(context, id + "pattern1", {
"entities" : definition.ticLine,
"transforms" : [rotation],
"instanceNames" : [id + "instance1"]
});
});
Thank you for your answer. I converted the axis to a line with evAxis and used that on rotationAround, but unfortunately it still doesn't work. So this is my code now:
FeatureScript 2455; import(path : "onshape/std/common.fs", version : "2455.0"); annotation { "Feature Type Name" : "Tics", "Feature Type Description" : "" } export const myTics = defineFeature(function(context is Context, id is Id, definition is map) precondition { annotation { "Name" : "Line", "Filter" : GeometryType.LINE, "MaxNumberOfPicks" : 1 } definition.ticLine is Query; annotation { "Name" : "Axis", "Filter" : GeometryType.LINE, "MaxNumberOfPicks" : 1 } definition.axis is Query; annotation { "Name" : "step:" } isReal(definition.step, POSITIVE_REAL_BOUNDS); } { var lineAxis = evAxis(context, {"axis" : definition.axis}); var rotation = rotationAround(lineAxis, -45 * degree); opPattern(context, id + "pattern1", { "entities" : definition.ticLine, "transforms" : [rotation], "instanceNames" : [id + "instance1"] }); });take the id out of the instanceNames array should be just a string
Hi Aleksi,
Good luck with your FS. there is another way though, leveraging Variables in feature patterns. read this and adapt accordingly.
https://www.onshape.com/en/resource-center/tech-tips/tech-tip-how-to-use-variables-in-patterns-to-vary-features
There's a custom feature to make this simpler, but I'm not sure it'll work for your logarithmic function.
https://cad.onshape.com/documents/b48de632f33db2e4ec9ffacd/w/33301ef2e5423da1a2dbda12/e/78553bdfcca3eb9f40c3e229?renderMode=0&uiState=66f3cb17b8d0b13781551dd2
@aleksi_hermonen.
Couldn't help myself but test it. this function ends up working exponentially and gets away from you rather quickly in the higher values.
circular pattern 2 is reapplied each and every time within Circular pattern 1 so it keeps adding a new line at a new angle, but measured from the original top line. (not from the line next to it)
https://cad.onshape.com/documents/2c9655258e3035ca1e88e8b7/w/69535d4d989a936765ab897e/e/101ed463e2646a893e4f9fbf?renderMode=0&rightPanel=variableTablePanel&uiState=66f3d154662cd1376e8e28da