1. Increase the number of samples: increasing the number of samples (or samples) in the rendering settings can effectively reduce the graininess. Increasing the number of samples will increase the calculation time, but it can improve the rendering quality.
2. Change the rendering settings: It is also helpful to adjust other parameters in the rendering settings. For example, try adjusting the ray tracing depth, oscillation rate, or shadow settings.
3. Use noise reduction function: Many rendering software provide noise reduction function, which can improve image quality through noise reduction. Try to enable the noise reduction option in the rendering software and adjust the parameters to get a smoother and clearer image.