Rib, Web, and Emboss

Overview#

Three Create-menu tools add detail to existing bodies without you having to model every wall by hand.

• Rib creates a thin feature from an open sketch profile, in a direction parallel to the sketch plane, extruded to the nearest faces on a solid body. It is a common way to add stiffeners to housings, brackets, and plastic parts.
• Web creates a thin feature from an open sketch profile, in a direction perpendicular to the sketch plane, extruded to the nearest faces on a solid body; drawing several crossing curves can produce a lattice such as the internal grid of a molded tray.
• Emboss raises or recesses a sketch profile (including text, as long as the font is not a single-line font) relative to faces on a solid body, and can wrap text around a body.

All three work on solid bodies and are timeline features. Each is quicker and more robust than hand-drawing the same walls with Extrude, because they find the boundaries of the body for you.

Where to find it#

• Workspace: Design.
• Tab / panel: Solid tab > Create > Rib, Create > Web, Create > Emboss.
• Shortcut: none listed in Autodesk's shortcut reference.
• If you cannot see a command, search for it with S. Rib and Web are separate tools with similar dialogs; the difference is the build direction relative to the sketch plane (see below).

Step by step#

Rib#

1. Make a hollow part or a part with a pocket. Choose the sketch plane that cuts through the cavity, such as the mid-plane of a box.
2. Sketch an open line or polyline where the rib should sit. It need not touch the body walls; Rib extends to them.
3. Finish the sketch and choose Create > Rib.
4. Select the sketch profile.
5. Set the Thickness Direction (Symmetric extrudes half the thickness to each side of the profile; One Side/One Direction extrudes the full thickness to one side), Start (Top or Bottom: where thickness is measured from), Thickness, and Extent Type (To Next, or Depth with a distance).
6. Optionally add a Draft Angle, Draft Pull Direction and Fillet Radius (part of the Fusion Design Extension), then OK. Click the Flip icon if the rib builds the wrong way.

Web#

1. In a shelled body, sketch open lines representing the center lines of a grid of webs on a plane through the cavity.
2. Choose Create > Web and select the sketch curves.
3. Set the Thickness Direction, Start, Thickness and Extent Type (To Next or Depth).
4. Leave Extend Curves checked to extend the web beyond the ends of the sketch profile to the nearest faces on the body; uncheck it to stop the web at the ends of the profile. Then confirm.

Emboss#

1. Create a sketch with text (Sketch > Text) or other 2D profiles on a plane near the target face. Text must not use a single-line font. In parametric designs the emboss stays linked to the sketch, so editing the sketch updates it.
2. Choose Create > Emboss.
3. Select the Sketch Profiles (text letters or shapes).
4. Select the Faces to emboss onto (uncheck Tangent Chain if you do not want tangent neighbors selected automatically).
5. Choose the Effect: Emboss adds material, Deboss removes it. Enter Depth (a positive value embosses, a negative value debosses; changing the sign switches the Effect) and use Flip Normal to flip the normal side of the selected profiles.
6. Use Alignment (Horizontal Distance, Vertical Distance, Rotation Angle) to position the artwork on the face, then click OK.

Options reference#

Names below follow Autodesk's Rib, Web and Emboss reference pages. The Draft Angle, Draft Pull Direction and Fillet Radius fields of Rib and Web are marked in Autodesk's help as part of the Fusion Design Extension.

Tips and pitfalls#

Tip: A rib sketch can be a single line on a plane that bisects the part. Add a rib in one pass, then use Mirror or a Rectangular Pattern of the feature to repeat it.

Tip: For 3D printing (general guidance, not Autodesk data), use fonts with thick strokes and emboss at least 0.6 mm so the text survives slicing. Thin serif fonts can disappear.

Warning: Rib thickness equal to the wall thickness is commonly said to cause sink marks on injection-molded parts. This is a general design guideline, not a Fusion error; check it with your manufacturer.

Warning: If Rib fails, the profile sketch may not lie between solid walls, or the build direction may face empty space. Move the sketch plane so it passes through the solid region and use the Flip icon (general troubleshooting).

Warning: Emboss on a heavily curved or small face can fail or distort letters. Use a smaller font, lower depth, or a flatter target face.

• Rib and Web both require a solid body, not a surface.
• A rib extended To Next meets a sloped inner wall automatically; you do not need to shape the rib end.
• In parametric designs, emboss features keep their link to the original sketch; if you edit the sketch, the Emboss updates.
• For a large number of items, consider embossing one and patterning it.
• Autodesk says Emboss can wrap text around a solid body (not single-line fonts); use Alignment to position the artwork and check legibility where curvature is steep.
• The Draft and Fillet fields of Rib and Web are Fusion Design Extension features, so they may be unavailable without that extension.

Rib design with numbers#

Ribs add stiffness without adding the mass of a thicker wall. The table below gives general plastics-design rules of thumb (not Autodesk data) that also tend to apply to 3D printing:

Stiffness scales roughly with the cube of height, so a rib 9 mm tall adds far more stiffness than three ribs 3 mm tall. For a rectangle, bending stiffness goes as thickness x height^3 / 12: a 1.5 mm wide, 9 mm tall rib is 1.5 x 729 / 12 = 91 mm4 by itself, while a 1 mm wide strip of the 3 mm plate is only 1 x 27 / 12 = 2.25 mm4. The rib contributes far more stiffness per gram than thickening the wall.

Rib or Web?#

Both tools take an open sketch profile and extrude to the nearest faces of a solid body. Autodesk's difference is direction: Rib builds in a direction parallel to the sketch plane, Web in a direction perpendicular to it. Web also has an Extend Curves checkbox; with it off, the web stops at the ends of your sketch curves.

Rib workflow and the Direction setting#

With Symmetric, a 2 mm thickness puts 1 mm on each side of the sketch line, so the rib is centered on your line. With One Direction/One Side the full 2 mm goes to one side. Start (Bottom or Top) sets where thickness is measured from. When positioning a rib exactly at a hole center line, use Symmetric; for a rib that must be flush with a wall, use One Direction and flip it as needed.

To Next stops at the first solid faces it finds. If the sketch plane passes through a void, the rib spans from wall to wall; if there is an obstacle (a boss), it stops at the boss. Depth gives a fixed height, which is the safer choice when the part may change.

Emboss in practice#

Because Emboss can wrap onto a curved surface, letters near the edges of a cylindrical face are seen at a steeper angle; keep wrapped text modest in width and check the preview. General FDM guidance (not Autodesk data): a depth of about 0.8 mm suits a 0.4 mm nozzle, text smaller than about 6 mm high prints poorly, and stroke widths of at least 0.8 mm (two perimeters) are safer. Use a bold sans serif font for printing; thin strokes and fine serifs can disappear in slicing.

Worked example: ribbed lid#

1. Create a 100 x 60 x 3 mm plate (the lid).
2. Sketch a centerline on a plane that cuts the plate's top; for a rib on the underside, sketch on the XY plane and use Direction One Direction toward the plate.
3. Rib: Thickness 1.5 mm, Extent Type Depth 8 mm, Symmetric. Add Fillet Radius 0.75 mm if you have the Fusion Design Extension.
4. Add a second sketch with two crossing diagonals and make a Web with Thickness 1.5 mm, Depth 6 mm, Extend Curves on.
5. Emboss "LID" 0.6 mm on the top, Alignment: Horizontal Distance 0, Vertical Distance 10 mm.

Failure modes and fixes#

Practice exercise#

Stiffen a shelled lid and add a label, measuring each design decision.

1. Model a 100 x 60 x 40 mm box and Shell it 2 mm with the top face removed.
2. Sketch a diagonal line on the mid-height plane across the inside. Create a Rib: Symmetric, Thickness 1.2 mm (60 percent of the 2 mm wall, a general guideline), Extent To Next. Measure the rib thickness.
3. Create a second rib using Extent Type Depth 10 mm and compare how it behaves if you later change the box height to 50 mm (To Next follows the walls; Depth does not).
4. Sketch two crossing lines on the floor plane and make a Web: Thickness 1.2 mm, Depth 8 mm, Extend Curves on. Repeat with Extend Curves off and note the end condition.
5. Sketch the text "LAB 01", 10 mm high, on the front face. Emboss 0.8 mm; then change Depth to -0.8 mm to Deboss (the Effect switches automatically). Adjust Alignment to center the text.
6. Pattern the first rib twice with 25 mm spacing, then calculate the new stiffness benefit: rib height 38 mm vs. wall 2 mm.

Expected result: a rigid box with ribs and a web grid, and a label you can raise or sink by changing Depth sign. Record which rib settings follow the box when its height changes.

Related#

• Extrude (the manual alternative)
• Shell, Draft, Scale (creating the cavity for ribs)
• Fillet and chamfer (rib root radii)
• Text in the sketching section