1. User Interface: RealtimeBoard offers a visually appealing and intuitive interface with a focus on visual collaboration tools such as whiteboards, sticky notes, and mind maps. In contrast, Redmine has a more traditional and text-based interface primarily designed for project management and issue tracking.

2. Collaboration Features: RealtimeBoard emphasizes real-time collaboration where multiple users can work simultaneously on the same board, making it ideal for brainstorming and teamwork. Redmine, on the other hand, provides collaboration features through comments and notifications but does not offer real-time editing capabilities like RealtimeBoard.

3. Primary Use Case: RealtimeBoard is tailored for design thinking, product development, and creative ideation with an emphasis on visual representation and brainstorming. Redmine, on the other hand, is primarily used for project management, issue tracking, and software development with a focus on task management and progress tracking.

4. Integration Capabilities: RealtimeBoard offers seamless integration with popular tools such as Slack, Trello, Jira, and Google Drive, allowing users to streamline their workflow and connect different aspects of their work. In contrast, Redmine has limited integration options and may require additional plugins or customization for integrating with other tools.

5. Mobile Support: RealtimeBoard provides a mobile app for users to access and collaborate on boards from their mobile devices, enabling flexibility and on-the-go productivity. Redmine, on the other hand, lacks dedicated mobile support, which may limit accessibility and convenience for users who prefer mobile access.

6. Cost Structure: RealtimeBoard operates on a subscription-based model with tiered pricing plans based on the number of users and features required, offering a scalable solution for teams of different sizes. In comparison, Redmine is an open-source project management tool that is free to use but may require additional costs for hosting, customization, and support services.

In Summary, RealtimeBoard and Redmine differ in user interface, collaboration features, primary use case, integration capabilities, mobile support, and cost structure, catering to different needs and preferences in visual collaboration and project management.