File Extension THR File Format Pro/ ENGINEER (PTC) THR stands for Pro/ ENGINEER (PTC). This was last updated in March 2012 By Margaret Rouse Browse File Extensions Alphabetically: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # Ask a Question. Find an Answer. Ask your peers a question about this file extension. Ask a Question Vendor PTC makes play for augmented reality technology To be a full-stack engineer, get out of your comfort zone Should I invest in formal SDN training, certification?