<p>Thick-panel origami structures are able to deploy into expansive configurations, making them suitable for industrial applications such as deployable stadium domes, water-tight roof tiling, sun shields, furniture, antennas, solar arrays, space telescopes, etc. Existing methods often introduce structural complexities or fail to ensure seamless surfaces, limiting their practicality. Here our process involves modifying valley-crease panels and extending adjacent panels to eliminate grooves, thus achieving a seamless surface. The paper presents the geometric conditions for ensuring motion compatibility and analyzes the kinematics of the modified structures. Additionally, an approach for minimizing the number of top panels is proposed to simplify fabrication and enhance lightweight design. Prototypes of these designs are 3D-printed to validate the concepts. The methods and results offer valuable insights for developing deployable structures with customizable shapes and enhanced functionality.</p>