Edit the value of a joint already created.

[JHRendon]

Hi! I'm working with a robotic arm that i designed and I want to control it making "inverse kinematics".

So, the point is that i select the joints of the robotic arm and with all the calculations joints move to the position that i want. 

The problem is how can I edit this joints. 

I know that first i need to select the joints:

        ui.messageBox('Select a Joint, please')

        selectedItem1 = ui.selectEntity("Select a Joint", "Joints")

        selectedItem1Value = selectedItem1.entity

I do not know if this would be the right way to select the joint to modify it, but if it is, how can i modify its value? 

        angle = adsk.core.ValueInput.createByString('190 deg')

        selectedItem1Value.angle = angle

this way it is not working. 😞

if someone knows how can i take a joint already created and modify it when i run an add-ins, please tell me 🙂

[MichaelT_123]

Hi Mr JHRendon,

Perhaps as a starter reading/immersing into respective sample codes available in F360 docs (search <JointMotion Sample>) would be of benefit. The subject could be tricky from time to time so, to avoid drowning I would suggest to have  two hands handy 😉.

Regards

MichaelT

[kandennti · Accepted solution]

Hi JHRendon.

[BasicTraining]-[Assemblice]-[GenevaDrive] data was used.
Execute the following script and select [Joints]-[Rev1] to start rotation.

#Fusion360API Python script
#Author-kantoku
#Description-joint angle test

import adsk.core, adsk.fusion, traceback

def run(context):
    ui = None
    try:
        app  :adsk.core.Application = adsk.core.Application.get()
        ui   :adsk.core.UserInterface = app.userInterface

        msg :str = 'Select a Joint'
        selFiltter :str = 'Joints'
        sel :adsk.core.Selection = SelectEnt(ui, msg ,selFiltter )
        if sel is None:
            return

        jnt :adsk.fusion.Joint = sel.entity

        for v in range(0,360,10):
            jnt.angle.expression = str(v)
            app.activeViewport.refresh()

        ui.messageBox('Done')

    except:
        if ui:
            ui.messageBox('Failed:\n{}'.format(traceback.format_exc()))

def SelectEnt(
        ui :adsk.core.UserInterface,
        msg :str, 
        filtter_str :str) -> adsk.core.Selection :

    try:
        selection = ui.selectEntity(msg, filtter_str)
        return selection
    except:
        return None

[JHRendon]

Thanks a lot!!! 😄 

[kandennti · Accepted solution]

I created a sample but it seems to have been deleted.
It is very disappointing.

#Fusion360API Python script
#Author-kantoku
#Description-joint angle test2

import adsk.core, adsk.fusion, traceback

def run(context):
    ui = None
    try:
        app  :adsk.core.Application = adsk.core.Application.get()
        ui   :adsk.core.UserInterface = app.userInterface
        des = adsk.fusion.Design.cast(app.activeProduct)
        root = des.rootComponent

        jnt :adsk.fusion.Joint = root.joints.itemByName('Rev1')
        if not jnt:
            ui.messageBox('Joint not found')
            return
        
        msg = 'Please enter an angle(unit-degree)\n(Cancel-ESC)'
        (iptAngStr, cancelled) = ui.inputBox(msg)
        if cancelled or not isfloat(iptAngStr):
            return

        ang :adsk.fusion.ModelParameter = jnt.angle
        beforeAng = ang.value

        import math
        afterAng = math.radians(float(iptAngStr))

        diff = afterAng - beforeAng

        if abs(diff) < 0.01:
            return
        
        if diff > 0:
            step = 0.1
        else:
            step = -0.1

        for v in floatRange(beforeAng, afterAng, step):
            ang.value = v
            app.activeViewport.refresh()
        ang.value = afterAng
        app.activeViewport.refresh()

        ui.messageBox('Done ( {} )'.format(ang.expression))

    except:
        if ui:
            ui.messageBox('Failed:\n{}'.format(traceback.format_exc()))

def floatRange(begin, end, step):
    n = begin
    if step > 0:
        while n + step < end:
            yield n
            n += step
    else:
        while n + step > end:
            yield n
            n += step

def isfloat(string):
    try:
        float(string)
        return True

    except ValueError:
        return False

[JHRendon]

THANKS A LOT!! You're amazing! 😄