i’m preparing a script for classical architecture moldings
and trying to complete the cyma reversa
but it looks like it is not the opposite or the mirror of the cyma recta?
on diagonal angle is at 45 D while the other one is at 50 degrees?
anybody can give me some feedback on this difference and why ?
see pic
Happy blendering
No they are not simple opposites or mirrors of each other . But both forms are related via the inscription of the S curve within a circle using a single unit of measure . From what I gather the names recta and reversa have more to do with the concave/convex nature of the curves (relative to the “normal”/perpendicular line - this is why your image is wrong on the reversa diagram) . But yes you do derive both from the same set of curves and lines …
Here’s a blend explaining it :
CYMA.blend (180 KB)
it would appear that there might be more than one way to do it
depends what soure of info you take
here is one that i found by luck
see pic
depends where you set the center of the circles
and if you want a thin or thick curve
also this is not an ogee curve at least not from math point of view
theses where created in the middle ages or even maybe before that in greek or roman time
Thanks
also this is not an ogee curve at least not from math point of view
I did not know that an ogee curve had a mathematical formula necessarily …
As some one who has worked with S curves in design (mostly in furniture), I can tell you the S curve is usually not a math based design element . It is just a nice visual element how ever you apply/derive it .
All I was trying to do was to explain the old mason’s and ancient Greek technique/rules based on the use of the compass . Which BTW led them to the old “squaring of the circle” problem that Archimedes almost solved and which wasn’t totally abandoned until the calculus (it seems that old Archie almost got to calculus using “squaring of the circle” methods) …
In your new image fig. 20 & 21 look like they are using a half based radius for the curves, while fig. 22 & 23 look like they are using the same base one radius like your previous example .
well if you worked in wood furniture
do you have any doc or info on the use of the golden number
on motifs or moldings
i was unable to find anything on the web
i know that i saw a TV program on wood leg design and there is a way to make a wood leg using the golden number to make the shape of the leg
and may be it is also used in other shapes too
do you have any info on this golden number subject
i’m preparing a script to do basic moldings classical
like between 20 to 30 different type of moldings including the cyma recta and cyma reversa beak ect…
and will continue after that doing other script for classical architecture
like rose window and trefoil ect…
i meant there are so many motifs in classical architecture that can be done with script to save a lot of time to draw theses and complete piece of classical architectur
be it from roman greek or gothic era!
Happy blendering
Here are some basic links to the “golden ratio” or phi and also a goofy link to the Fibonacci series (which is also of interest to art and architecture) :
http://jwilson.coe.uga.edu/EMT669/Student.Folders/Frietag.Mark/Homepage/Goldenratio/goldenratio.html
http://www.mcs.surrey.ac.uk/Personal/R.Knott/Fibonacci/fibnat.html
In the first link where he shows the various geometry based on phi is what artists and architects use to shape various motifs .
Sorry I don’t know of any specific links that uses phi in a direct manner (maybe be the Wiki article has better links in the arts section - I didn’t look through them) …
Sounds like an interesting project . Good Luck !
i already had the one from wikipedia on golden number
the other seem more about flowers ect,
but nothing yet on applications in architecture
i heard there are books on this but may be not free on the web !
Thanks