hello, I hope you all are well,

So i am trying to draw the logarithmic profile on Spaceclaim, of the equation 𝛿(𝑟,𝑡)=Δ∙[1−(𝑟^2/𝑟𝑐^2)+(2∙𝑟^2/𝑟𝑐^2)∙ln(𝑟/𝑟𝑐)]. I am unable to write down the natural log of the equation on spaceclaim. i mean spaceclaim does not recognize ln() or Log() or LOG() or log(), instead it just turns my sketch into a straight line. Please help!