Writing a measured value to a variable in the model tree and keeping it updated.

Chris_Loughnane

Essentially I'm trying to recreate a 'sensor' or User-Defined Measurement. In the simplest case I have an arc, would like to evaluate it's length, then store that number in a variable so that I can reference it later in my model tree. 

I'm just jumping into featurescript so it's not immediately obvious to me how to do this, if I can do it, or if it's already been done.

kevin_o_toole_1

Check out Measure Distance Extended, written by @konstantin_shiriazdanov
https://cad.onshape.com/documents/77baa8153589a7fc5f289829/w/cffd0f2a7077380d5378a885/e/d3174bf5315e6aafcb889367

abefeldman

Check out this custom feature:  https://cad.onshape.com/documents/572b968ce4b07aad125dbaaf/v/08093fef6c4d4f330f24dd19/e/b40df94c5081948fe8195e81

Chris_Loughnane

Using the suggestions above made a slight adjustment in order to measure length

<div>annotation { "Feature Type Name" : "Measure Length", "Feature Name Template" : "###name = #value", "UIHint" : "NO_PREVIEW_PROVIDED" } &nbsp; &nbsp;</div><div>export const measureLength = defineFeature(function(context is Context, id is Id, definition is map)</div><div>&nbsp; &nbsp; precondition</div><div>&nbsp; &nbsp; {</div><div>&nbsp; &nbsp; &nbsp; &nbsp; annotation { "Name" : "Name", "Default" : "length" }</div><div>&nbsp; &nbsp; &nbsp; &nbsp; definition.name is string;</div><div><br></div><div>&nbsp; &nbsp; &nbsp; &nbsp; annotation { "Name" : "First entities", "Filter" : EntityType.EDGE }</div><div>&nbsp; &nbsp; &nbsp; &nbsp; definition.first is Query;</div><div><br></div><div>&nbsp; &nbsp; &nbsp; &nbsp; // annotation { "Name" : "Second entities", "Filter" : EntityType.FACE || EntityType.EDGE || EntityType.VERTEX || EntityType.BODY }</div><div>&nbsp; &nbsp; &nbsp; &nbsp; // definition.second is Query;</div><div><br></div><div>&nbsp; &nbsp; &nbsp; &nbsp; // annotation { "Name" : "Maximum" }</div><div>&nbsp; &nbsp; &nbsp; &nbsp; // definition.maximum is boolean;</div><div>&nbsp; &nbsp; }</div><div>&nbsp; &nbsp; {</div><div>&nbsp; &nbsp; &nbsp; &nbsp; if (!match(definition.name, '[a-zA-Z_][a-zA-Z_0-9]*').hasMatch)</div><div>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; throw regenError(ErrorStringEnum.VARIABLE_NAME_INVALID);</div><div>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;</div><div>&nbsp; &nbsp; &nbsp; &nbsp; const lengthResult is ValueWithUnits = evLength(context, {</div><div>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "entities" : definition.first</div><div>&nbsp; &nbsp; &nbsp; &nbsp; });</div><div><br></div><div>&nbsp; &nbsp; &nbsp; &nbsp; // if (!tolerantEquals(p0, p1))</div><div>&nbsp; &nbsp; &nbsp; &nbsp; // {</div><div>&nbsp; &nbsp; &nbsp; &nbsp; // &nbsp; &nbsp; debug(context, line(p0, p1 - p0));</div><div>&nbsp; &nbsp; &nbsp; &nbsp; // &nbsp; &nbsp; debug(context, line(p1, p0 - p1));</div><div>&nbsp; &nbsp; &nbsp; &nbsp; // }</div><div>&nbsp; &nbsp; &nbsp; &nbsp; // else // If it's the same point, just draw the point</div><div>&nbsp; &nbsp; &nbsp; &nbsp; // {</div><div>&nbsp; &nbsp; &nbsp; &nbsp; // &nbsp; &nbsp; debug(context, p0);</div><div>&nbsp; &nbsp; &nbsp; &nbsp; // }</div><div><br></div><div>&nbsp; &nbsp; &nbsp; &nbsp; setVariable(context, definition.name, lengthResult);</div><div><br></div><div>&nbsp; &nbsp; &nbsp; &nbsp; setFeatureComputedParameter(context, id, { "name" : "value", "value" : lengthResult });</div><div>&nbsp; &nbsp; });</div><br>