Read out hinge/servo value [SOLVED!]

Anton_S

Limited joint API is one of the weakness of SP. However, there is a workaround using Trigonometry, just like you said.

Here is an example:

Bas9999

Hi Anton_S,

Thank you for the example, i am going to study it a bit!

First i have to make the degrees to a value 0.00 (MIN) and 1.00 (MAX) (optional, but handy)

My goal is to put an Arduino behind the sketch, so that virtual pulled elements are also moving in the 'real' world, like a servo, i will put my project on the forum when it's finished

Best Regards,
Bas

Bas9999

Ok, i got it working to make a value from 0.00 to 1.00 from the degree number in the sketch above.

Since i am new to ruby i had todo some reseach but made it, if you have any improvements...let me know!

in section "onUpdate" add this at the end:

anglefloat = @angle.radians.round.to_f
puts (((0.5 / 90) * anglefloat) + 0.5).round(2) if anglefloat > 0
puts (((-0.5 / 90) * anglefloat) - 0.5).abs.round(2) if anglefloat < 0

Open the RUBY CONSOLE there you can see the values:

0.54
0.53
0.53
0.53
0.52
0.51
0.51
0.49
0.49
0.48
0.48
0.47
0.46
0.46
0.45
0.44
0.43
0.43
0.42
0.41
0.41
0.4
0.39

lever_angle2.skp

Bas9999

Hmmmm, seems the ROUND function is not doing well in SU8

After some research i made this code for SU8, using SPRINTF:

anglefloat = @angle.radians.round.to_f
puts sprintf "%.2f", (((0.5 / 90) * anglefloat) + 0.5) if anglefloat > 0
puts sprintf "%.2f", (((-0.5 / 90) * anglefloat) - 0.5).abs if anglefloat < 0

That seems to do the trick...

lever_angle2_SU8.skp

Anton_S

You get this error cause you probably passed an argument to the round function. SU2013 and below have no parameters in the round function, meanwhile, SU2014+ do have a decimal_point parameter in the round function.

Here is an improved version that gives value b/w 0.0 and 1.0.

lever_angle2_SU8.skp

Bas9999

Hello Anton_S,

Can the same be done with a slider?, could you provide an example?

Thanks!

slider_su8.skp

Anton_S

Here it is. This is more advanced script as it works with slider, piston, corkscrew, and spring. You just paste the script into any object, and its joint will be found automatically - no need to locate the connected joint and stuff... Just copy and paste. I might also write a similar script to hinge, servo, and motor.

Here is script that you copy and paste into any object:

<span class="syntaxdefault">onStart </span><span class="syntaxkeyword">{<br /></span><span class="syntaxdefault">  </span><span class="syntaxcomment"># Add 2D text, just to output info.<br /></span><span class="syntaxdefault">  setVar</span><span class="syntaxkeyword">(</span><span class="syntaxstring">'text_v_shift'</span><span class="syntaxkeyword">,</span><span class="syntaxdefault"> getVar</span><span class="syntaxkeyword">(</span><span class="syntaxstring">'text_v_shift'</span><span class="syntaxkeyword">)</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">+</span><span class="syntaxdefault"> 0.04</span><span class="syntaxkeyword">)<br /></span><span class="syntaxdefault">  </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">text </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> Sketchup</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">active_model</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">add_note</span><span class="syntaxkeyword">(</span><span class="syntaxstring">''</span><span class="syntaxkeyword">,</span><span class="syntaxdefault"> 0.01</span><span class="syntaxkeyword">,</span><span class="syntaxdefault"> getVar</span><span class="syntaxkeyword">(</span><span class="syntaxstring">'text_v_shift'</span><span class="syntaxkeyword">))<br /></span><span class="syntaxdefault">  </span><span class="syntaxcomment"># Find connected slider<br /></span><span class="syntaxdefault">  </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">slide_parent </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> nil<br />  </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">slider </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> nil<br />  </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">joint_name </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> nil<br />  parent_joints </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> this</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">group</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">get_attribute</span><span class="syntaxkeyword">(</span><span class="syntaxstring">"SPOBJ"</span><span class="syntaxkeyword">,</span><span class="syntaxdefault"> </span><span class="syntaxstring">"parentJoints"</span><span class="syntaxkeyword">).</span><span class="syntaxdefault">to_a<br />  parent_joints</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">each </span><span class="syntaxkeyword">{</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">|</span><span class="syntaxdefault">jname</span><span class="syntaxkeyword">|<br /></span><span class="syntaxdefault">    if jname </span><span class="syntaxkeyword">=~</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">/</span><span class="syntaxdefault">slider</span><span class="syntaxkeyword">|</span><span class="syntaxdefault">piston</span><span class="syntaxkeyword">|</span><span class="syntaxdefault">spring</span><span class="syntaxkeyword">|</span><span class="syntaxdefault">corkscrew</span><span class="syntaxkeyword">/</span><span class="syntaxdefault">i<br />      </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">joint_name </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> jname<br />      break<br />    end<br />  </span><span class="syntaxkeyword">}<br /></span><span class="syntaxdefault">  next unless </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">joint_name<br />  </span><span class="syntaxcomment"># Find slider associated with joint name<br /></span><span class="syntaxdefault">  Sketchup</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">active_model</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">entities</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">each </span><span class="syntaxkeyword">{</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">|</span><span class="syntaxdefault">e</span><span class="syntaxkeyword">|<br /></span><span class="syntaxdefault">    next unless e</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">is_a</span><span class="syntaxkeyword">?(</span><span class="syntaxdefault">Sketchup</span><span class="syntaxkeyword">;;</span><span class="syntaxdefault">Group</span><span class="syntaxkeyword">)</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">||</span><span class="syntaxdefault"> e</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">is_a</span><span class="syntaxkeyword">?(</span><span class="syntaxdefault">Sketchup</span><span class="syntaxkeyword">;;</span><span class="syntaxdefault">ComponentInstance</span><span class="syntaxkeyword">)<br /></span><span class="syntaxdefault">    if e</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">get_attribute</span><span class="syntaxkeyword">(</span><span class="syntaxstring">'SPJOINT'</span><span class="syntaxkeyword">,</span><span class="syntaxdefault"> </span><span class="syntaxstring">'name'</span><span class="syntaxkeyword">,</span><span class="syntaxdefault"> </span><span class="syntaxstring">''</span><span class="syntaxkeyword">)</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">==</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">joint_name<br />      </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">slider </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> e<br />    else<br />      found </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> false<br />      e</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">entities</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">each </span><span class="syntaxkeyword">{</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">|</span><span class="syntaxdefault">ec</span><span class="syntaxkeyword">|<br /></span><span class="syntaxdefault">        if ec</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">is_a</span><span class="syntaxkeyword">?(</span><span class="syntaxdefault">Sketchup</span><span class="syntaxkeyword">;;</span><span class="syntaxdefault">Group</span><span class="syntaxkeyword">)</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">&&</span><span class="syntaxdefault"> ec</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">get_attribute</span><span class="syntaxkeyword">(</span><span class="syntaxstring">'SPJOINT'</span><span class="syntaxkeyword">,</span><span class="syntaxdefault"> </span><span class="syntaxstring">'name'</span><span class="syntaxkeyword">,</span><span class="syntaxdefault"> </span><span class="syntaxstring">''</span><span class="syntaxkeyword">)</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">==</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">joint_name<br />          </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">slider_parent </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> e<br />          </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">slider </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> ec<br />          found </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> true<br />          break<br />        end<br />      </span><span class="syntaxkeyword">}<br /></span><span class="syntaxdefault">      break if found<br />    end<br />  </span><span class="syntaxkeyword">}<br /></span><span class="syntaxdefault">  next unless </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">slider<br />  </span><span class="syntaxcomment"># Get min/max data associated with a slider<br /></span><span class="syntaxdefault">  slider_min </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">slider</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">get_attribute</span><span class="syntaxkeyword">(</span><span class="syntaxstring">'SPJOINT'</span><span class="syntaxkeyword">,</span><span class="syntaxdefault"> </span><span class="syntaxstring">'min'</span><span class="syntaxkeyword">,</span><span class="syntaxdefault"> 0</span><span class="syntaxkeyword">)<br /></span><span class="syntaxdefault">  slider_max </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">slider</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">get_attribute</span><span class="syntaxkeyword">(</span><span class="syntaxstring">'SPJOINT'</span><span class="syntaxkeyword">,</span><span class="syntaxdefault"> </span><span class="syntaxstring">'max'</span><span class="syntaxkeyword">,</span><span class="syntaxdefault"> 0</span><span class="syntaxkeyword">)<br /></span><span class="syntaxdefault">  </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">slider_range </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">(</span><span class="syntaxdefault">slider_max </span><span class="syntaxkeyword">-</span><span class="syntaxdefault"> slider_min</span><span class="syntaxkeyword">).</span><span class="syntaxdefault">to_f<br /></span><span class="syntaxkeyword">}<br /><br /></span><span class="syntaxdefault">onUpdate </span><span class="syntaxkeyword">{<br /></span><span class="syntaxdefault">  if </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">slider<br />    </span><span class="syntaxcomment"># Calculate object position and ratio on slider.<br /></span><span class="syntaxdefault">    pt </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> this</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">group</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">transformation</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">origin<br />    if </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">slider_parent<br />      tra </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">slider_parent</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">transformation </span><span class="syntaxkeyword">*</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">slider</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">transformation<br />    else<br />      tra </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">slider</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">transformation<br />    end<br />    pt</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">transform</span><span class="syntaxkeyword">!(</span><span class="syntaxdefault">tra</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">inverse</span><span class="syntaxkeyword">)<br /></span><span class="syntaxdefault">    pos </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> pt</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">z<br />    ratio </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">slider_range</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">zero</span><span class="syntaxkeyword">?</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">?</span><span class="syntaxdefault"> 0 </span><span class="syntaxkeyword">;</span><span class="syntaxdefault"> pos </span><span class="syntaxkeyword">/</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">slider_range<br />    </span><span class="syntaxcomment"># Process info here...<br /></span><span class="syntaxdefault">    </span><span class="syntaxcomment"># Display info<br /></span><span class="syntaxdefault">    </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">text</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">text </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> </span><span class="syntaxstring">"#{@joint_name.capitalize} Info - Position; #{sprintf("</span><span class="syntaxkeyword">%</span><span class="syntaxdefault">.2f</span><span class="syntaxstring">", pos)}\"    Ratio (Controller); #{sprintf("</span><span class="syntaxkeyword">%</span><span class="syntaxdefault">.2f</span><span class="syntaxstring">", ratio)}"<br /></span><span class="syntaxdefault">  end<br /></span><span class="syntaxkeyword">}<br /><br /></span><span class="syntaxdefault">onEnd </span><span class="syntaxkeyword">{<br /></span><span class="syntaxdefault">  </span><span class="syntaxcomment"># Remove added text<br /></span><span class="syntaxdefault">  </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">text</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">erase</span><span class="syntaxkeyword">!</span><span class="syntaxdefault"> if </span><span class="syntaxkeyword">@</span><span class="syntaxdefault">text</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">valid</span><span class="syntaxkeyword">?<br />}</span><span class="syntaxdefault"></span>

Here is the demo:
slider_range_su8.skp

Also, I would suggest upgrading to SP3.5.6 as the pick and drag in 3.5.5 makes small objects go crazy.

Bas9999

Hello anton_S,

Again, thank you for the example code!, i see it's a lot for a NON Sketchup/Ruby expert like me

I needed this for a virtual "RGB LED controller" that controls a LED trough the Arduino, so i made some adds & adjustements to your code.

Ps. why does the value start at 0.06 and ends with 1.07?, i did a correction of -0.6 but then i still come out on 1.01

My additions to store the 3 RGB values per slider:

RED:

onupdate {
    ratio = ratio - 0.06
    ratio = 1.00 if ratio > 1.00
    $sliderr = sprintf("%.2f", ratio)
}

GREEN:

onupdate {
    ratio = ratio - 0.06
    ratio = 1.00 if ratio > 1.00
    $sliderg = sprintf("%.2f", ratio)
}

BLUE:

onupdate {
    ratio = ratio - 0.06
    ratio = 1.00 if ratio > 1.00
    $sliderb = sprintf("%.2f", ratio)
}

On the "baseplate" this code in the "scripted" section to display the values on the left side:

onUpdate {
logLine("Waarde rood; " + $sliderr.to_s)
logLine("Waarde groen; " + $sliderg.to_s)
logLine("Waarde blauw; " + $sliderb.to_s)
logLine("")
logLine("")
logLine("")
logLine("")
logLine("")
}

Here is a screen of the project:
SketchUp SketchPhysics - RGB control 02.png

SketchUp SketchPhysics - RGB control.skp

Anton_S

@bas9999 said:

Ps. why does the value start at 0.06 and ends with 1.07?, i did a correction of -0.6 but then i still come out on 1.01

Because joints in SP are flexible. They are not 100% stiff.

To fix that, simply clamp the given values from 0 to 1:
ratio = 0.0 if ratio < 0.0 ratio = 1.0 if ratio > 1.0

Bas9999

Hi Anton_S,

Thank you!

Ps. the first script for the "hinge", is that also a copy & paste script for every component?, if not... could you adjust it that way?

Thanks in forward!

Anton_S

Here is the script for hinge, servo, motor, and corkscrew:


# Script for hinge, servo, motor, and corkscrew.
onStart {
  # Add 2D text, just to output info
  setVar('text_v_shift', getVar('text_v_shift') + 0.04)
  @text = Sketchup.active_model.add_note('', 0.01, getVar('text_v_shift'))
  # Find connected joint
  @joint_parent = nil
  @joint = nil
  @joint_name = nil
  parent_joints = this.group.get_attribute("SPOBJ", "parentJoints").to_a
  parent_joints.each { |jname|
    if jname =~ /hinge|servo|motor|corkscrew/i
      @joint_name = jname
      break
    end
  }
  if @joint_name
    # Find joint group associated with joint name
    Sketchup.active_model.entities.each { |e|
      next unless e.is_a?(Sketchup;;Group) || e.is_a?(Sketchup;;ComponentInstance)
      if e.get_attribute('SPJOINT', 'name', '') == @joint_name
        @joint = e
      else
        found = false
        e.entities.each { |ec|
          if ec.is_a?(Sketchup;;Group) && ec.get_attribute('SPJOINT', 'name', '') == @joint_name
            @joint_parent = e
            @joint = ec
            found = true
            break
          end
        }
        break if found
      end
    }
  end
  if @joint
    # Get min/max data associated with the joint
    min = @joint.get_attribute('SPJOINT', 'min', 0).to_f
    max = @joint.get_attribute('SPJOINT', 'max', 0).to_f
    @range = (max - min).degrees
    # Calculate starting angle
    if @joint_parent
      tra = @joint_parent.transformation * @joint.transformation
    else
      tra = @joint.transformation
    end
    @init_dir = tra.xaxis.transform(this.group.transformation.inverse)
    @init_angle = min.degrees
  end
}

onUpdate {
  if @joint
    # Calculate object angle and ratio
    if @joint_parent
      tra = @joint_parent.transformation * @joint.transformation
    else
      tra = @joint.transformation
    end
    dir = @init_dir.transform(this.group.transformation).transform(tra.inverse).normalize
    # Get theta from -PI to PI
    theta = -Math.acos(dir.x)
    theta = -theta if dir.y < 0
    ratio = @range.zero? ? 0 ; (theta - @init_angle).to_f / @range
    # Process info here...
    # Display info
    @text.text = "#{@joint_name.capitalize} Info - Angle; #{sprintf("%.2f",  theta.radians)} deg.    Ratio (Controller); #{sprintf("%.2f", ratio)}"
  end
}

onEnd {
  # Remove added text
  @text.erase! if @text.valid?
}

And here is the updated script for slider, piston, spring and corkscrew. This version considers initial position, so that range values are correct:


# Script for slider, piston, spring, and corkscrew.
onStart {
  # Add 2D text, just to output info
  setVar('text_v_shift', getVar('text_v_shift') + 0.04)
  @text = Sketchup.active_model.add_note('', 0.01, getVar('text_v_shift'))
  # Find connected joint
  @joint_parent = nil
  @joint = nil
  @joint_name = nil
  parent_joints = this.group.get_attribute("SPOBJ", "parentJoints").to_a
  parent_joints.each { |jname|
    if jname =~ /slider|piston|spring|corkscrew/i
      @joint_name = jname
      break
    end
  }
  if @joint_name
    # Find joint group associated with joint name
    Sketchup.active_model.entities.each { |e|
      next unless e.is_a?(Sketchup;;Group) || e.is_a?(Sketchup;;ComponentInstance)
      if e.get_attribute('SPJOINT', 'name', '') == @joint_name
        @joint = e
      else
        found = false
        e.entities.each { |ec|
          if ec.is_a?(Sketchup;;Group) && ec.get_attribute('SPJOINT', 'name', '') == @joint_name
            @joint_parent = e
            @joint = ec
            found = true
            break
          end
        }
        break if found
      end
    }
  end
  if @joint
    # Get min/max data associated with the joint
    min = @joint.get_attribute('SPJOINT', 'min', 0).to_f
    max = @joint.get_attribute('SPJOINT', 'max', 0).to_f
    @range = (max - min).to_f
    # Calculate starting position
    pt = this.group.transformation.origin
    if @joint_parent
      tra = @joint_parent.transformation * @joint.transformation
    else
      tra = @joint.transformation
    end
    pt.transform!(tra.inverse)
    @init_pos = pt.z + min
  end
}

onUpdate {
  if @joint
    # Calculate object position and ratio
    pt = this.group.transformation.origin
    if @joint_parent
      tra = @joint_parent.transformation * @joint.transformation
    else
      tra = @joint.transformation
    end
    pt.transform!(tra.inverse)
    pos = pt.z - @init_pos
    ratio = @range.zero? ? 0 ; pos / @range
    # Process info here...
    # Display info
    @text.text = "#{@joint_name.capitalize} Info - Position; #{sprintf("%.2f", pos)}\"    Ratio (Controller); #{sprintf("%.2f", ratio)}"
  end
}

onEnd {
  # Remove added text
  @text.erase! if @text.valid?
}

Demo

Anton_S

This is amazing! Never seen something like this before, ever!

mptak

Stupendous. Can't wait to try it and of course add some Lasers. Absolutely stupendous. Kudos to y'all Anton and Chris Phillips.

Bas9999

Thank you Anton_S!

@All,
Watch the YouTube movie where i used these scripts in action:

SCRIPTS & TUTORIALS @ DomoticX.com
Look for: "Virtual 3D Device Port"

The tutorial pages are written in our main language: DUTCH
Use google translate to translate the pages for you!

(note: copy & paste scripts from the original untranslated site)