Format Latex report Chapter, Section, Subsection header styles

I'm writing my thesis and instructions for chapter, section and subsection are as following.

``````- Chapter heading :All Capital—14 Font size, Bold
- Section heading :Title case-12 Font size, Bold
- Sub-section heading :Sentence case-12 Font size, Bold
- Body text :Sentence case - 12 Font size
``````

Further I'm having "subsubsections" also. I'm trying to implement these using `titlesec`. My problems are how to capitalize chapter heading?. How to implement "title case" and "sentence case"? Thanks in advance.

``````\usepackage{titlesec}
\titleformat{\chapter}{\normalfont\large\bfseries}{\thechapter}{14pt}{\large}
\titleformat{\section}
{\normalfont\bfseries}{\thesection}{12pt}{}
\titleformat{\subsection}
{\normalfont\bfseries}{\thesubsection}{12pt}{}
\titleformat{\subsubsection}
{\normalfont\bfseries}{\thesubsubsection}{12pt}{}
``````
• What is an example of "title case" and "sentence case", just so it's clear to everyone? I really think such case-settings should form part of the name. That is, rather `Some Title` than `\titlecase{some title}`. – Werner Dec 19 '14 at 5:07
• @Werner : "title case" as in your example, is having every first letter capitalized (Ex. Example Title) and sentence case is with out capitalization (Ex. example title). – Nilani Algiriyage Dec 19 '14 at 5:23
• So you plan on using `\chapter{this is my long chapter title}`, `\section{a beautiful section}` and `\subsection{SoMeTHiNG}` and you want it to be formatted as `THIS IS MY LONG CHAPTER TITLE` and `A Beautiful Section` and `SoMeTHiNG`. Font-changing and size are easy, but the capitalization is a bit much, just because it's something that is best kept the way you type it (you can use the Converting Text to Title Case and/or the `titlecaps` package). – Werner Dec 19 '14 at 5:50