How to evaluate an expression in dimension text

There is no way to automatically add text into a particular hole dimension. That being said it sounds like what you need is a custom hole note. Some threads on hole notes:

CALLOUT_FORMAT in *.hol files‌

tapped hole parameters

UNEF thread

Summary CB and CS .hol files

modifing UNF.hol file - help!!

In particular you might want to change the DEPTH_RATIO to 2 (see below as an example)

TABLE_DATA
PRO_VERSION      24
THREAD_SERIES    TAP
CLASS            H
TABLE_UNITS      metric
DEPTH_RATIO      2.00
CALLOUT_FORMAT  &METRIC_SIZE x &THREAD_DEPTH[.0] DP /(&PATTERN_NO x)

My preferred method of doing this is to use a reference to the depth dimension. If there is an actual feature in the model for the tapped hole, it must have an accompanying depth dimension, so you can just reference that. Something like:

M&diameter, &depth DEEP

Or whatever your preferred nomenclature is for tapped holes. The &size is the dimension for the hole diameter or thread or whatever, the &depth is the dimension ID for the depth of the hole.

I really don't like putting plain text into dimensions specifying things like depths and the like because they do not reflect the actual model, so if someone in the future realizes that you actually need 3 diameters of depth because the hole is in something weak, like acrylic, they might change the model but unless they manually change the dimension text the change won't show up on the drawing.

Sorry for not making my question clear.

I want to know whether we can evaluate an expression in dimension text (hole note is also ok). 

I can achieve what I described in my example by editing a custom hole chart, but that is not what I want to do. It is just an example of a case where being able to use expressions in notes or dimension texts is helpful.

Here is what I am working on.

I want to create reaming holes with notes or dimension text.

For example, to make a Φ3.1 reaming hole in the model, and have the text "Φ3.1 reaming hole depth 5, thru" (Just an example, thru means the original hole is a through hole) ready when click "show model annotation" in drawing.

The reaming depth (5) should not be plain text, it must be a value retrieved from the model.

I was thinking of several methods to achieve this.

1. Drill two holes at the same location, one is Φ3 through and the second is Φ3.1 with the depth equal to the depth of our reaming hole. I can format the note for this Φ3.1 hole and only show it when click "show model annotation"

The problem with this approach is, when we make hole tables, both holes will appear. We only need the Φ3.1 one. It is possible to delete the Φ3 hole from hole table, but with hundred of reaming holes, it will be impractical (by the way, if there is a way to do that, please tell me.)

We can not make only one hole for the Φ3.1, because we want a small through hole. If we don't make that through hole in the model, the model will be different from what we actually want and problems may arise later.

The problem will be solved if we can use an expression to get the depth (5) from the reaming diameter (3.1) (eg. floor(2*Φ)). Then we can drill only one Φ3.1 through hole and use the note with the calculated depth.

2. Use user defined function.

When we drill a hole (without note), edit dimension text, and create an UDF with that hole, any future holes created with that UDF will have the same dimension text. So if we format the dimension text as, for example @D depth &d8 (d8 is the depth of the hole), any holes created with that UDF will readily have a dimension text with its diameter and depth. 

The problem her is that in our case, the hole is through, we don't need d8, we need something like  @D depth floor(2*@D)

Unfortunately, 2*@D is not something recognized by Creo, and I could not find any syntax for an expression in dimension text (maybe it doesn't exist).

So, in short, i) I want to make a hole feature, whose note (or dimension text) readily includes its diameter and reaming depth (so that I can just show model annotation and don't need to make any new dimension text or note for the feature.) ii) That reaming depth should depend on the feature (not plain text). and iii) The feature should appear as one hole in a hole table.

If somehow I can write an expression that can be evaluated in dimension texts or notes (eg. if Φ = 2 and the expression means 2Φ, the evaluated value of 4 should appear in the dimension text or hole note). 

I greatly appreciate all your help. Thank you for reading this long question.