buildingSMART Forums

Is the IFC entities are case senstive?

#1

Greetings for the day,
Can anyone please help me to know that IFC entities are case sensitive or not.
For example, if I use “ifcproduct” or “IfcProduct” instead of “IFCPRODUCT” in .ifc file it is right or not.
Thank you.

0 Likes

IFC entities are case sensitive or not?
#2

Technically, parsers might accept non-case sensitive keywords, however, if you wanted to be correct to the STEP ISO 10303 specification it has to be all UPPERCASE.

Read more here: http://www.steptools.com/stds/step/IS_final_p21e3.html

This is the particular WSN of token definitions which defines the need to be uppercase:

KEYWORD           = USER_DEFINED_KEYWORD | STANDARD_KEYWORD .

USER_DEFINED_KEYWORD = "!" UPPER { UPPER | DIGIT } .

STANDARD_KEYWORD  = UPPER { UPPER | DIGIT } .
0 Likes

#3

Same time class names in EXPRESS scheme are camel-cased.
And I saw a lot of examples of AP with low letters.
I would say use capital for writing but be case-insensitive when read.

It seems documentation misses this question for property names. I expect case-insensitive.

0 Likes

#4

I believe the grammar for SPF (10303-21) says that KEYWORDS should be saved with capital letters, the abstract SDAI spec (22) says that express_id (name of named_type) should be in lower case, but there is mentioned that (11) says that case of letters is not significant for EXPRESS identifiers, so in .exp files can be all ways of naming, even CamelCase as in IFC .exp s.

However .exp files for AP2XX schemas have identifiers as in (22), in lower case. Probably CamelCase and lower case is better for .exp files because EXPRESS ENTITY/TYPE/SELECT etc. are with capital letters, for better reading.

Access seems can be case insensitive.

0 Likes

#5

Greetings for the day,
According to the work I have done with IFC and found that Yes the IFC entities are case sensitive.

I have performed the extraction of some entities from the IFC file and create a new IFC. If the new IFC file contains entities written in a format other then upper-case i.e, lower-case or camel-case the IFC file doesn’t work.
Thank you.

1 Like