The shadow effect on my model is blurred when i turn on a texture plain. Is this because of the sun angle, and if so, how can i adjust the sun angle?
A Textured Plane should not cause reduced overall shadow clarity. You may try the following:
1. In Options>3D View>Advanced>Driver, try using DirectX11. You will need to close and restart Synchro for this to take effect
2. In Options>3D View>Advanced>Driver Options, try increasing Anti-aliasing (eg. to 4x) this will increase crispness of diagonal lines
3. In Options>3D View>Lighting Intensity, you can change the ambient (background) and diffuse (directional) light
4. Apply a Project Global Light - when applied the sun is stationary, otherwise the shadows depend on the camera angle. Right click in the 3D view and choose Effects>Use Project Global Light. To change the sun angle, hold Ctrl on the keyboard and left click on a corner or edge of the Viewcube (to show the Viewcube, right click in the 3D View and choose Visual Indicators>Axis Indicator)
5. If you have an Iray license, you may change the rendering settings (inclding Time of Day, Sun Altitude, and Sun Brightness) in 3D View Properties>Raytrace Option