In order to effectively create something new and with a significant level of complexity, one must have time in which one is entirely free from distraction. This time is necessary to allow one to properly focus on the task of creation. Thus, if one works in any sort of technical support or on call capacity, then there may be no possibility of effective creation at work, because the two tasks are exclusive.
Therefore, if working in such a capacity, then effective creation must be done when one is not “on call.” Which, in such a situation, is necessarily one’s free time. Of course, what one creates in their free time with their own resources should belong to that one, provided it does not utilize proprietary information or intellectual property belonging to others. Agreements may stilulate otherwise, but if the situation is I have described, than those agreements are parasitic and an evil to the creator.
I’d offered to create several things for my most recent employer, which would involve them giving me the necessary distraction free time and resources to do the work and would have entitled them to ownership, but my offers were refused. I decided that this was a mistake on behalf of my late employers, and I have taken all necessary steps to correct it, which has involved my leaving the company to insure my ownership of my work.