To ensure that certain features cannot be modified at a  later time,.you can 
make them read-only.
The dimensions, attributes, scheme, and so on of read-only  features can not be 
modified and are not regenerated when the part is  regenerated. However, you can 
add features to the parts that intersect the  read-only features.
When you make a feature read-only, Pro/ENGINEER makes it,  and all the features 
that came before it in the regeneration list, read-only. 
	1. Select the feature in the Model Tree or in the  graphics window.
	2. Click Edit > Read Only.  The R-ONLY FEAT menu appears.
	3. Click one of the following commands:
	* Select—Pick a feature to make it and all  previous features read only.
	* Feat  Num—Enter a feature external identifier to make it and all previous  
features read-only.
	* All  Feat—Make all features read-only.
	* Clean—Remove the read-only setting from  the features.
	1. Click Done/Return.