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dataVisualizationAndOutput

Data visualization/output

Data in CoppeliaSim can be visualized or output/logged in various ways:

web-browser based front-end

visualizing data in graphs

displaying data in custom user interfaces

augmenting the scene with visual items

logging data to the status bar via the simple print command

logging data to the status bar and/or terminal via the sim.addLog API function

logging data to a file

Following example illustrates how to display a joint angle in a simple custom user interface:

function sysCall_init()
    jointHandle=sim.getObject('/Joint')
    local xml =[[<ui title="Example" closeable="false" layout="form">
        <label text="joint angle:" />
        <label id="1" text="-" />
        </ui>]]
    ui=simUI.create(xml)
end

function sysCall_sensing()
    local v=180*sim.getJointPosition(jointHandle)/math.pi
    simUI.setLabelText(ui,1,string.format('%.3f',v))
end

function sysCall_cleanup()
    simUI.destroy(ui)
end

Augmenting the scene with visual items

Simple visual items such as points, lines, spheres or individual triangles can easily be added to the scene via API functions sim.addDrawingObject and sim.addDrawingObjectItem, for example:

function sysCall_init()
    local drawingObject=sim.addDrawingObject(sim.drawing_spherepts,0.005,0,-1,1000,{1,0,0})
    for i=0,359,1 do
        local coord={math.cos(i*math.pi/180),math.sin(i*math.pi/180),0.01}
        sim.addDrawingObjectItem(drawingObject,coord)
    end
end

More complex items, such as random meshes can be created on the fly via sim.loadModel, simAssimp.importShapes, sim.createPrimitiveShape, sim.createMeshShape and/or sim.copyPasteObjects. To avoid surcharching the scene with too many additional objects, make sure to group them with sim.groupShapes. For example:

function sysCall_init()
    local individualShapes={}
    for i=0,359,1 do
        local shape=sim.createPrimitiveShape(sim.primitiveshape_cylinder,{0.005,0.005,0.02})
        local coord={math.cos(i*math.pi/180),math.sin(i*math.pi/180),0.01}
        sim.setObjectPosition(shape,-1,coord)
        sim.setShapeColor(shape,nil,sim.colorcomponent_ambient_diffuse,{1,0,0})
        individualShapes[i+1]=shape
    end
    -- Group individual shapes:
    local masterShape=sim.groupShapes(individualShapes,true)
    -- Make it invisible to collision detection, sensors, etc.:
    sim.setObjectSpecialProperty(masterShape,0)
end

Logging data to a file

Following example illustrates how to log a joint angle to a file:

function sysCall_init()
    jointHandle=sim.getObject('/Joint')
    file=io.open('jointAngles.txt','w+')
    file:write('Joint angles for each simulation step:\n\n')
end

function sysCall_sensing()
    local v=180*sim.getJointPosition(jointHandle)/math.pi
    file:write(string.format('time: %.3f [s]',sim.getSimulationTime()+sim.getSimulationTimeStep()))
    file:write(string.format(', joint angle: %.1f [deg]\n',v))
end

function sysCall_cleanup()
    file:close()
end

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