The "Spiral Vase" is a special printing mode that prints the outer wall through only one perimeter and gradually increases the Z height by spiraling upward. In this way, apart from the bottom shell layers, there is no starting point and end point in the perimeter of each layer, and there is no "scar" like seams on the surface of the model (please refer to Seam | Bambu Lab Wiki), which can greatly improve the quality of the model surface.
The following two images are a comparison of the normal mode and the spiral vase mode. You can see that the surface of the model in the "Spiral Vase" mode has no seams.
"Spiral Vase" mode can be enabled in Bambu Studio, under the Others tab → Special mode
When you confirm that you want to enable the spiral vase mode, it will automatically adjust the Settings to set the outer wall layer to 1, the top shell layer to 0, and the sparse infill density to 0% :
However, it should be noted that the model printed in the spiral vase mode only has one loop wall, without infill and top shell. Therefore, it is only applicable to some models with relatively simple structures. If a model with a complex structure is printed in this mode, it may have suspended parts because it cannot be completed through a single perimeter, as shown in the figure below:
If you wish to print multiple objects simultaneously using the "Spiral vase" mode in one plate, please choose the "By object" Print sequence.