The Problem: You’ve applied the Round Corner plugin (by Fredo6) to a flat surface or a box, expecting a smooth, continuous fillet. Instead, the top face generates a visible crack, a jagged line, or completely separates into two distinct halves. Visually, it looks like the rounded edge "breaks" the surface of your object.
Why Does This Happen? The "cracked top" is not a bug per se, but a geometric limitation. It typically occurs when:
How to Fix or Prevent the Crack
1. Reduce the Radius (The Quick Fix) This is the most common solution. If your top face is 10mm thick, do not use a 6mm rounding radius. The radius should never exceed half the thickness of the smallest adjacent face.
2. Adjust the Round Corner Parameters The plugin offers advanced settings to mitigate this:
3. Repair After Generation If the crack appears but the model is otherwise correct:
4. Pre-Model the Corner Profile Instead of applying Round Corner to a raw box:
When to Accept the Crack If the model is strictly for 3D printing or rendering (not for structural editing), a minor top crack is often harmless. Use Solid Inspector (by ThomThom) – if the crack is a hairline and doesn't create a hole, the object remains a "solid group" and prints fine.
Final Check Always run Right-click → Reverse Faces on your object before using Round Corner. Ensure all exterior faces are white (front). A mix of front/back faces is a guaranteed way to get cracks on top surfaces.
Seeing "cracks" or gaps on the top face of your SketchUp model after using a rounding tool is a common headache. It usually happens when the geometry gets too complex for the plugin to calculate cleanly, or when SketchUp's internal "tiny face" limit is triggered. Common Causes of "Cracks"
The "Tiny Face" Problem: SketchUp has a hard time creating faces smaller than ~1/16th of an inch (1.6mm). When you round a corner with many segments, the resulting triangles at the very top can be so small that SketchUp fails to fill them, leaving a "crack" or hole.
Tight Corner Overlap: If your rounding radius (offset) is larger than the distance to the next edge, the plugin "overflows" and creates overlapping or broken geometry.
Non-Planar Surfaces: If the top face isn't perfectly flat, the plugin may struggle to "stitch" the new rounded geometry to the existing face, resulting in visible seams or missing surfaces. How to Fix and Prevent Cracks
When modeling in SketchUp, few things are as frustrating as using the RoundCorner extension only to have it "crack" or leave messy holes in your top faces. This usually happens when the geometry is too small or complex for the plugin to calculate cleanly.
Here is how to identify, fix, and prevent the "sketchup round corner crack top" issue. 1. The "Dave Method" (Scaling Up)
The most common cause of cracks is SketchUp's inability to create very small faces (less than ~1/16th of an inch). When the plugin tries to round a small corner, it simply fails to fill the geometry, leaving a "crack". The Fix: Select your object and make it a Component.
Make a copy of that component and scale it up by 100x or 1000x. Run the RoundCorner plugin on the giant version.
Close the component and delete the giant copy. Your original-sized component will now have the rounded corners perfectly filled in because the math was done at a larger scale. 2. Check for Overlapping Offsets
If your rounding offset is larger than the distance between two edges, the geometry will "overlap," causing the plugin to produce red warning lines and eventually "cracked" or missing faces.
The Fix: Reduce your Offset value in the plugin toolbar until the preview shows clean, green lines without red intersections. If you must have a large radius, you may need to simplify the surrounding geometry first. 3. Cleaning Up "Cracked" Top Faces
Sometimes the rounding works, but the top face of your object disappears or becomes fragmented.
Manual Healing: Turn on Hidden Geometry (View > Hidden Geometry) to see the missing segments.
Redraw Edges: Often, simply drawing a single line across the "crack" or over an existing edge will trigger SketchUp to "heal" the face and fill the hole.
Delete Extraneous Faces: In some cases (like rounding a hole), the plugin may leave the original top face floating. Select and delete it to reveal the rounded geometry underneath. 4. Software & Extension Maintenance sketchup round corner crack top
If the plugin is crashing your entire SketchUp session ("cracking" the software itself), it is likely a version conflict. Round corner doesnt work correctly - SketchUp Forums
Introduction
SketchUp is a popular 3D modeling software used by architects, interior designers, and product designers. One of the common issues faced by SketchUp users is the "Round Corner Crack Top" error. This report aims to provide an overview of the issue, its causes, and possible solutions.
What is Round Corner Crack Top?
The "Round Corner Crack Top" error occurs when using the "Round Corner" or "Fillet" tool in SketchUp to create rounded corners on a 3D model. The error causes the top surface of the model to become distorted or "cracked" when trying to apply a rounded corner.
Causes of Round Corner Crack Top
After analyzing various user reports and forums, the following causes have been identified:
Solutions
The following solutions can help resolve the "Round Corner Crack Top" error:
Workarounds
If the above solutions do not resolve the issue, the following workarounds can be tried:
Conclusion
The "Round Corner Crack Top" error in SketchUp can be caused by complex geometry, insufficient faces, or incorrect tool settings. By simplifying geometry, increasing faces, adjusting tool settings, or using alternative tools, users can often resolve the issue. If necessary, workarounds such as manual modeling or using third-party plugins can also be employed.
Recommendations
Mastering SketchUp: How to Fix "Crack Top" and Geometry Issues in Round Corners
If you’ve spent any time 3D modeling, you’ve likely encountered the frustrating "crack top" or broken geometry issue when trying to round off a corner in SketchUp. This typically happens when the software's internal engine struggles to calculate complex intersections, often resulting in missing faces or "cracks" on the top surface.
While SketchUp is incredibly versatile, it wasn't natively designed for complex edge rounding. To get professional results, you’ll almost always need a specialized extension or a few expert workarounds. 1. Why Do "Cracks" Appear?
The "crack top" issue usually stems from one of three problems:
The Tiny Face Problem: SketchUp has difficulty forming very small faces (under 1mm or 1/16 inch). When you round a corner with a high segment count, the resulting faces may be too small for SketchUp to "heal," leaving a gap or crack.
Non-Planar Top Surfaces: If the top face of your object isn't perfectly flat, standard rounding tools will fail to calculate how the curve should meet the surface, leading to geometric "tears".
Too Large an Offset: If your rounding radius (offset) is larger than the available surface area, the geometry will overlap and break the top face. 2. Best Solutions: FredoCorner vs. RoundCorner
The most common way to solve this is by using extensions from developer Fredo6. There are two primary options, and knowing which one to use is key to avoiding top-face cracks.
FredoCorner (Recommended): This is the newer, more powerful tool. It uses an improved algorithm that handles complex, irregular shapes much better than its predecessor. It includes a Repair button and parametric abilities, allowing you to edit or undo rounding if it creates a crack. Troubleshooting the "Cracked Top" Issue in SketchUp's Round
RoundCorner (Legacy): While simpler and faster for basic cubes, it is "greedier" with face generation and often fails on non-orthogonal edges. If one fails, many pros keep both installed as a backup. 3. Step-by-Step Fix for Cracked Geometry
If your top face is cracking, follow these steps to achieve a clean finish:
Scale Up (The "Dave Method"): Before applying any rounding, scale your entire model up by 10x or 100x. This bypasses the "tiny face" limitation. Once the rounding is finished, scale it back down—the tiny faces will remain intact.
Reduce Segment Count: A common mistake is using too many segments (e.g., 12 or 24) for a small corner. Lowering this to 6 segments is often enough for a smooth look while keeping the geometry manageable and less prone to breaking.
Check for Overlaps: Use the Preview mode in FredoCorner to see if your offset is too large. If the preview shows red or overlapping lines, reduce the radius until they disappear.
Manual Re-topping: If a crack persists, delete the broken top face, round the edges, and then use a tool like Curviloft or the native "Create Face" tools to manually stitch the top back together. 4. Native Alternatives (No Plugins)
If you prefer not to use extensions, you can use the Follow Me tool: Curved face problem - SketchUp Forums
In SketchUp, "cracking" on a top face when using the RoundCorner plugin (by Fredo6) is a classic frustration caused by the software’s internal limit on processing tiny geometry. This often looks like missing triangles or "shattered" surfaces near the rounded edges.
Here is the "story" of why this happens and how you can fix it. 1. The Mystery of the "Tiny Face" Limit
SketchUp has a built-in tolerance of about 1/1000th of an inch. If you are rounding a corner and the segments of that curve are so small that the distance between points is less than this limit, SketchUp decides they are the "same" point. It merges them, fails to create the tiny face, and leaves you with a "cracked" or hole-filled top surface. 2. Solving it with "The Dave Method"
The most reliable way to fix these cracks is a workflow known in the community as the Dave Method:
Create a Component: Select your object and turn it into a component.
Scale Up a Copy: Make a copy of that component and scale it up significantly (e.g., 100x or 1000x).
Run the Plugin: Use RoundCorner on the large copy. Because the geometry is now huge, SketchUp has no trouble creating all the faces.
The Result: Because they are instances of the same component, the original small version will update automatically with perfectly healed geometry. You can then delete the giant copy. 3. Other Common "Crack" Culprits If scaling up doesn't work, check these potential issues:
The "Hole" Glitch: Sometimes rounding a hole in a surface leaves the original top face "floating" over the curve. You often just need to manually delete that overlapping face to reveal the smooth rounding underneath.
Over-Segmentation: Using too many segments for a small radius creates unnecessary complexity that increases the chance of cracks. Six segments are usually plenty for a standard rounded edge.
Excessive Offset: If your "Offset" (the radius of the curve) is larger than the face itself, the geometry will overlap and "crack". Ensure your offset doesn't exceed the distance to the next edge. 4. Manual Patching
If the crack is small and you don't want to redo the operation: RoundCorner | SketchUcation
Post: Struggling with the SketchUp Round Corner extension? 🧩
If you get a "cracked top" (faceted artifacts on a flat surface after filleting), here is the fix:
👉 Turn OFF "Triangulate" in the advanced settings. 👉 Or, apply the fillet before punching a hole in the top face.
The extension is powerful, but it hates Ngons that aren't perfectly planar. If the crack persists, use Curvizard to weld the perimeter after rounding. Overlapping Geometry: The rounding radius is so large
#SketchUp #3DModeling #Tips #RoundCorner
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Introduction
SketchUp is a popular 3D modeling software used by architects, interior designers, and makers. One of its useful features is the ability to create rounded corners and edges. However, some users may encounter a frustrating issue - a crack or gap at the top of a rounded corner. In this article, we'll explore the causes of this issue and provide solutions to fix the SketchUp round corner crack top.
What causes the SketchUp round corner crack top?
The crack or gap at the top of a rounded corner in SketchUp is usually caused by a few factors:
How to fix the SketchUp round corner crack top
To resolve the issue of a crack or gap at the top of a rounded corner in SketchUp, try the following solutions:
Step-by-Step Solution
Here's a step-by-step guide to fix the SketchUp round corner crack top:
Conclusion
When you encounter a "cracked" or missing top face after using the Fredo6 RoundCorner
plugin in SketchUp, it is usually due to the software's difficulty in creating tiny faces. SketchUcation Why Your Top Face is Cracking Tiny Face Limitation
: SketchUp has a hard time forming faces when edges are extremely short (typically under 1mm). When the plugin rounds a corner with high segments or small offsets, the resulting geometry can be too small for SketchUp to fill, leaving holes or "cracks". Complex Geometry
: Rounding holes or non-orthogonal intersections can sometimes confuse the algorithm, causing it to skip the top face or leave "bad geometry" at the corners. SketchUp Community How to Fix the "Cracked Top" Issue The "Scale Up" Method (Best Fix) Turn your object into a Make a copy and scale it up by 10x or 100x RoundCorner
to the giant copy. Because the geometry is now large, SketchUp will successfully generate all faces.
Delete the giant copy; the original-sized component will automatically be updated with the perfectly rounded (and filled) geometry. Manual "Healing" Hidden Geometry (View > Hidden Geometry) to see the missing segments. Trace over one of the missing edge segments with the
; SketchUp will often "heal" and refill the entire missing face. Adjust Plugin Parameters Reduce Segments
: If you don't need a super-smooth curve, lower the segment count (e.g., from 12 to 6) to create larger, more stable faces. Increase Offset
: A larger rounding radius creates larger faces that are easier for SketchUp to process. Try FredoCorner Fredo6 released a newer version of the tool called FredoCorner
, which uses a more advanced algorithm designed to handle complex triangulation and repair issues better than the original RoundCorner. SketchUcation native SketchUp tools to round corners manually if the plugin continues to fail? RoundCorner plugin issues - SketchUp Forum 10 Nov 2015 —
If the crack is a physical gap:
This is the culprit 90% of the time.
Sometimes, it is not your fault; it is SketchUp’s precision limits. SketchUp works in "units." If you are modeling a microchip (millimeters) and applying a 0.01mm round, the engine cannot calculate the arc.
The Fix:
