Grid, also called normal or linear, supports build straight columns in a crosshatched pattern under whatever needs holding up. Tree supports grow branching trunks that lean toward the model and touch it only at specific points. Both solve the same overhang problem, but they leave very different marks on the part and use very different amounts of material to do it.
Contact points versus contact area
Grid supports typically touch the part across a wider area directly beneath each overhang, which makes the support solid and predictable but leaves a larger scarred patch once it is removed. Tree supports narrow that contact down to individual tips, so a complex overhang might get a handful of small touch points instead of a full column. On visible surfaces or figures, that difference in scar size and count is often the deciding factor.
Material and print time
On a wide, flat overhang, grid supports fill the whole area underneath it, which costs real filament and time. Tree supports can route several nearby overhangs into one shared trunk, using noticeably less material on organic or angled shapes. The tradeoff is generation time in the slicer: computing a tree structure across a complex model takes longer than laying out a grid, and on a slow computer that difference is noticeable before you even start printing.
Where each one struggles
Grid supports handle wide flat overhangs reliably but waste material and time on organic shapes with awkward angles. Tree supports can leave a wide flat ceiling under-supported if the slicer’s tip spacing is too sparse for that particular surface, since a single branch tip is not built to hold up a broad flat area on its own. Neither style compensates for bad cooling, wrong orientation or a bridge that exceeds what the printer can actually do, the same limits covered in the general guide to when supports are needed.
What your slicer calls it
Cura has a dedicated tree support option alongside its normal grid supports. PrusaSlicer and OrcaSlicer call their branching option “organic” supports rather than “tree,” but it behaves the same way. Bambu Studio offers both normal and tree supports and defaults most users toward tree for anything with real overhangs. The settings that matter most in any of them are branch angle, tip diameter and the top interface gap, not just which style you pick.
Support style checklist
- Use grid supports under wide, flat overhangs where a solid column is genuinely needed.
- Use tree supports on organic shapes, miniatures and models with scattered overhangs to save material and reduce scarring.
- Check the layer preview either way, a support style choice does not replace verifying where support actually generates.
- Tune tip spacing on tree supports if a flat area comes out sagging or under-supported.