Orientation and Support Generation#

Overview#

Two decisions dominate the cost, quality and success of an additive part: which way it sits on the build plate, and what holds up the parts that would otherwise hang in air. They are linked, because orientation determines what needs support, and supports determine surface finish and post-processing effort. This page explains how to think about both and where Fusion helps. Supports may be generated in the slicer you hand the mesh to, or, for supported machines and licenses, in a Fusion additive setup in the Manufacture workspace. The principles apply to both.

Support needs depend on the process. FDM needs supports for steep overhangs and unsupported islands. Resin needs supports for nearly everything, since the part hangs from the plate. Polymer powder-bed needs none (the powder supports the part). Metal powder-bed needs supports for overhangs and to anchor the part and conduct heat. These are general process rules of thumb; check the specific options in your slicer or Fusion setup.

Where to find it#

The supports you can add depend on the machine in the setup. Per Autodesk, FFF offers Solid Volume and Solid Bar supports; SLA/DLP, MPBF, eBeam and binder jetting offer others such as Volume, Bar, Polyline and Base Plate or Setter supports. Volume, Surround Volume by Polyline and the other Polyline-family supports are marked as Fusion Manufacturing Extension features, and the SLA/DLP workflow notes that some supports need the extension.

Step by step#

Choosing an orientation#

1. List the constraints. Write down which face must be flat, which hole must be round, which direction the part is loaded, and which surfaces are cosmetic.
2. Try three candidate orientations: the natural flat face down, the second-largest face down, and a tilted orientation (15-45 degrees about one axis). For each, estimate support volume, height and print time.
3. Score the candidates. Consider:
   • Strength. Layers should be parallel to the principal load; avoid loads across layers.
   • Accuracy. Critical round holes with vertical axes print round; critical dimensions in XY are more accurate than in Z for most processes.
   • Surface. Faces on supports and bottom faces are rougher; tilted surfaces show stair-stepping.
   • Support volume and removal access. Fewer supports, easier to reach.
   • Height. Taller prints take more time (more layers) and are less stable; wide, low prints can be quicker.
   • Thermal behavior. For metal and some plastics, minimize large flat cross-sections in a single layer.
4. Pick the orientation and note it with the model, for instance in a text note in the Fusion document or in the 3MF filename.
5. Verify in preview. In the slicer's layer view, scrub through to check overhangs and islands.

Generating supports in a slicer (FDM example)#

1. Enable supports and select the type: normal/grid (strong, large contact) or tree/organic (less material, easier to remove).
2. Set overhang angle (support everything beyond this angle from vertical). Common: 45-55 degrees.
3. Choose support placement: everywhere or touching build plate only. Touching-plate-only keeps surfaces clean on the part's top surfaces at the cost of leaving some overhangs unsupported.
4. Set support density (10-20 percent typical) and pattern.
5. Set the Z gap (distance between support and part top) to roughly one layer height or slightly more, and the XY gap to about 0.3-0.8 mm. A bigger Z gap makes removal easier but leaves rougher underside.
6. Use interface layers (a dense roof) for smoother undersides; two to four layers is common.
7. Use support enforcers/blockers (painted regions) to add supports exactly where needed and prevent them where they would trap in a cavity or fuse to a delicate part.
8. Slice and preview. Look for supports that are tangled in internal channels you cannot reach.

Generating supports in a Fusion additive setup#

The flow below follows Autodesk's additive help. Which tools appear depends on the machine and, for some supports, on the Manufacturing Extension.

1. Open the Manufacture workspace and choose Additive > Setup > New Setup. Select the machine and, if needed, the print setting (the print setting is specific to the raw material). See the additive settings page.
2. Position the part with Additive > Position. Move Components rotates or translates it, Place on Platform drops it on the plate (or lays a selected flat face parallel to it), and Automatic Orientation runs a study.
3. In an Automatic Orientation study you set a Smallest Rotation (5 to 180 degrees), a Support Overhang Angle (0 to 90 degrees from horizontal), a Platform Clearance, and ranking priorities for Support Volume, Support Area, Bounding Box Volume, Part Height and Center of Gravity Height. Fusion then lists ranked orientation results to accept.
4. Use Additive > Supports. For an FFF machine, Solid Volume Support takes selected bodies or faces, a Support Overhang Angle (0 to 90 degrees from horizontal), an optional Avoid selection, and Top and Bottom Distance to Part gaps. Parameters for how supports are built live in the Print Setting editor.
5. Generate the additive toolpath, simulate it, then post a G-code file or generate a 3MF or machine-specific build file.

Designing supports into the model#

Sometimes the best support is one you design. For a part that prints on a hobby machine without good support options:

1. Create a thin sacrificial body in Fusion, such as a post under an overhang with a 0.2-0.3 mm gap to the part.
2. Keep it as a separate body in the same export so the slicer prints it.
3. Remove it after printing.

This is also how you create breakaway supports for specific features such as bridged holes.

Options reference#

Tips and pitfalls#

Tip: The best support is no support. Use chamfers, teardrops and orientation to avoid them; then compare the final surface quality with what supports would have given.

Tip: Support scars appear on the face where supports touch. Plan to put non-critical faces there, and do not put threads, bearing seats or sealing faces on a support face.

Warning: Do not enable supports "everywhere" on a part with internal holes or channels. Supports inside small channels cannot be removed and ruin the part. Use blockers and design channels to be self-supporting (diamond or teardrop).

Warning: For resin, supports are structural, not just cosmetic. Too few supports will cause detachment mid-print; too many leave scars. Start with automatic supports at medium density and add manual supports at islands.

Tip: For metal, ask the vendor about support design for your alloy; supports are also thermal paths, and cutting them off may require wire EDM or sawing, which needs access.

Warning: Tree supports are efficient but fragile; tall trees can wobble. Use them for organic models and use grid supports under large flat roofs.

Tip: After a first print, take notes: which supports were hard to remove, which overhangs sagged anyway. Feed the lessons into the model (add a chamfer, change an angle) rather than only adjusting slicer settings.

Removing supports#

• FDM. Use flush cutters, a hobby knife and needle-nose pliers. Support removal is easier when the part is warm or when interface gaps are generous. Sand or file scars. Soluble supports (PVA, HIPS or dedicated supports in dual-extruder machines) dissolve in water or limonene.
• Resin. Remove supports after a short rinse and before the final cure when the resin is a bit softer; follow the resin maker's guidance. Cut at the support tip, not the part.
• Polymer PBF. No supports; remove the powder.
• Metal PBF. Parts are usually stress relieved on the plate, cut off by wire EDM or saw, and supports are removed by hand tools or machining. Surfaces are then machined or blasted.

Practice exercise#

Take a model with a 40 mm horizontal arm sticking out from a vertical column (an L-shaped bracket). Slice it three ways: standing on the column, lying on its side, and tilted 45 degrees. Record the support volume and print time in your slicer for each. Then add a 45-degree gusset or chamfer under the arm in Fusion and slice the standing orientation again. Expected result: the lying orientation needs no support but may weaken the corner; the standing orientation needs support under the arm; the gusset removes the need for support entirely in the standing orientation, and strengthens the corner.

Related#

• FDM Design Guidelines
• Build Plate Arrangement and Nesting
• Additive Settings and Machine and Material Libraries
• SLS and Metal Additive Basics