Points and picas are normal for setting type in layouts for printed pages (newspapers, magazines, etc). In that realm the baseline grid, columns, etc matter more than the physical size of letters.
That points and picas stuff doesn't translate well to sign design. The physical size of the letters matters more there. If a customer wants a set of 24" tall channel letters the physical cap letter height has to be 24" tall, not some fraction of 24" and the remainder being varying amounts of invisible space depending on what typeface was chosen.
CorelDRAW doesn't have an option for sizing letters according to cap letter height, much less any added options for lowercase height. It isn't difficult to manually size a dummy cap letter like "E" to a desired height and copy the values to other text objects. I like how CorelDRAW allows text objects to be aligned to other objects via their baselines (as well as distribute multiple artistic text objects via baselines). I wish Adobe Illustrator could do that. Gotta fart with Smart Guides and manually snapping text objects to other things instead.
A couple or so versions ago Adobe Illustrator added some font height options; it defaults to the normal Em box but has options for cap letter height, lowercase letter height and the ICF box. Illustrator's implementation works reasonably well, but not always. It depends on the chosen font. The same has been true for Flexi and CASmate before that.
Every font file has built in dimensions to define baseline, cap height line, ascender and descender. At first glance it would seem easy for a graphics app to compute the difference between baseline and cap line and arrive at a solution for sizing letters according to physical cap letter size. Unfortunately not all fonts have their cap letters align neatly to the cap letter line. Plenty of sans serif fonts will undershoot or even overshoot the cap letter line. Certain scripts, such as Bickham Script Pro dramatically undershoot the cap letter line; I guess that is done to make room for all the big swooshes in those alternate characters.
So, in the end, there is no neat, one-size-fits-all solution to this problem.
That points and picas stuff doesn't translate well to sign design. The physical size of the letters matters more there. If a customer wants a set of 24" tall channel letters the physical cap letter height has to be 24" tall, not some fraction of 24" and the remainder being varying amounts of invisible space depending on what typeface was chosen.
CorelDRAW doesn't have an option for sizing letters according to cap letter height, much less any added options for lowercase height. It isn't difficult to manually size a dummy cap letter like "E" to a desired height and copy the values to other text objects. I like how CorelDRAW allows text objects to be aligned to other objects via their baselines (as well as distribute multiple artistic text objects via baselines). I wish Adobe Illustrator could do that. Gotta fart with Smart Guides and manually snapping text objects to other things instead.
A couple or so versions ago Adobe Illustrator added some font height options; it defaults to the normal Em box but has options for cap letter height, lowercase letter height and the ICF box. Illustrator's implementation works reasonably well, but not always. It depends on the chosen font. The same has been true for Flexi and CASmate before that.
Every font file has built in dimensions to define baseline, cap height line, ascender and descender. At first glance it would seem easy for a graphics app to compute the difference between baseline and cap line and arrive at a solution for sizing letters according to physical cap letter size. Unfortunately not all fonts have their cap letters align neatly to the cap letter line. Plenty of sans serif fonts will undershoot or even overshoot the cap letter line. Certain scripts, such as Bickham Script Pro dramatically undershoot the cap letter line; I guess that is done to make room for all the big swooshes in those alternate characters.
So, in the end, there is no neat, one-size-fits-all solution to this problem.