How can I add a RADIAL dimension?

I am trying to add a radial dimension via Python/RhinoCommon:

            dimension = Rhino.Geometry.RadialDimension(pCenter, pTip, vX, vZ, dOffset)
            id = doc.Objects.AddRadialDimension(dimension)

This works fine, but I (always) get a DIAMETER dimension instead of a RADIUS dimension. The property IsDiameterDimension is read only, so how can I define the type?

Hi fabian,

Can you make use of a user option via CommandLine (Radius or not Radius), like so? :

params = ("Radius", "No", "Yes")
isRadius = rs.GetBoolean("Radius", params, (False) )

dimension = Rhino.Geometry.RadialDimension(pCenter, ...
if isRadius[0]:
    dimension = dimension / 2
id = doc.Objects.AddRadialDimension(dimension)

// Rolf


not sure where to change the type but if you do not need a dynamic dimension you might try this ugly hack before adding it to the document:

dimension = Rhino.Geometry.RadialDimension(pCenter, pTip, vX, vZ, dOffset)
dimension.Text = "R{}".format(dimension.NumericValue*0.5) 
id = doc.Objects.AddRadialDimension(dimension)

Note that IsDiameterDimension still returns True, would be to easy, also tried to change diameter.Text to “R<>” but it remains a diameter dimension and that does not change the value, just the prefix…


Hi Rolf,

I don’t think this is gonna work, since dimension is created as an instance of Rhino.Geometry.RadialDimension. You can’t divide that by two and if you assign a float value to it AddRadialDimension won’t accept it as input anymore.

Using a command script would be the last resort of course, but if there’s a way to avoid this I’d rather go for “proper” programming…

Thanks anyway!

Hi clement,

thanks for the idea. Since the resulting model is to be exported as fabrication data both in Rhino and DWG-Format for a client, I’d rather have proper dynamic dimensions in there. But for printing PDFs I’ll just change the text.

Do you happen to have any idea how the TextFormula-property of the AnnotationBase-class is working?
The documentation is a bit minimalistic at this point…

Best, Fabian

Hi Fabian,

The TextFormula basically determines the format of the Text property. Use the angle brackets <> to determine the position of the NumericValue property.
For example the following dimension.TextFormula:

dimension.TextFormula = "Ø _something in here <>"

Will result in the the following dimension.Text:

"Ø _something in here 50"

(in case your NumericValue is 50)

Also if you are using the Ø character, make sure that you add the # coding=utf-8 on top of your script.

@djordje, @fabian,

i am not entirely sure if TextFormula is properly evaluated when used in a radial dimension. I thought that these only apply to Text fields, as described in the Rhino helpfile under “Text fields”. Eg if i try this on a circle with diameter 20:

radial_dimension.TextFormula = "Ø<> %<modelunits>%"

or this:

radial_dimension.Text = "Ø<> %<modelunits>%"

If just creates the radial dimension with this dimension text: Ø20 %<modelunits>%

The angle brackets can be used in the Text property too eg. using dimension.Text = "R<>" but as described in my first reply it still printed a diameter value instead of the radius.

If the dimension needs to stay dynamic, i’ve wondered if you couldn’t create a seperate dimension style with LengthFactor set to 0.5 and assign that after replacing the diameter symbol with R ? But i’d rather choose the static way and force the correct radius value to prevent errors in the downstream…

Maybe @dale can take a look why IsDiameterDimension is read only or has a fix for the problem ?


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