Troubleshooting
This page lists the warnings that appear in Builder and the situations where you get stuck, sorted into groups. Each heading starts with the text on the screen, with the cause and the fix below it. You can search this page for the text on your screen (Ctrl+F).
Most warnings appear as a short notification in the corner of the screen and stay for 3.5 seconds. If you missed the notification, do the same thing again.
Check the status indicators first
| Indicator | Meaning | What to do |
|---|---|---|
| "Saved" next to the project name in the Toolbar | The robot is in your account, and its latest version is saved. | You do not need to do anything. |
| "Not saved" next to the project name in the Toolbar | You changed the robot after you saved it to your account. The share link shows the old version. | Press the text. In the Save to my account window, press Save. |
| No save text next to the project name | The scene is not tied to a robot in your account. | Select File > Save to my account..., or open the robot from My robots.... |
| "Connecting" or "Not available right now" next to the account items in the File menu | Builder is connecting to the account server, or it cannot reach it. | See the first heading in the "Account and sharing" section below. |
| "N parts · N selected" in the status bar | The number of parts in the scene and the number of selected parts. | If a number is not what you expect, make the selection again. |
| "N hidden" in the status bar | Some parts in the scene are hidden. You cannot click a hidden part in the scene. | Right-click an empty spot in the Scene and select Show all (n). |
| Snap is orange, and the end of the status bar shows "2.5mm · 45° snap · 10 mm grid" | Snap is on. The part moves in 2.5 mm steps and snaps to holes. | To move freely, hold Shift or turn off Snap. |
| The end of the status bar shows "snap off · 10 mm grid" | Snap is off. The part moves freely, and the hole magnet does not work. | To seat the part in a hole, turn on Snap in the Toolbar. |
| "Mate · click the hole of the part to move" or "Mate · click the target hole" in the status bar | Mate is on, and Builder is waiting for you to click a hole. | Click the hole the text asks for. To leave, press Esc. |
| The Assembly strip below the Scene, with "Step N / M" in its title | The robot is in assembly mode. You cannot move, add or delete parts. | To make changes, press Switch to editing. |
| The "The scene is empty" card in the middle of the Scene | There are no parts in the scene. Try in Sim is faded, and you cannot save to your account. | On the card, press Starter Bot, Omni chassis or WattOS mecanum chassis, or press Parts list. |
| "Build passed" in the Build panel | The structure is connected, and there are no collisions. | You do not need to do anything. |
| "Built with warnings" in the Build panel | There are no errors, but there is at least one warning. | Look at the findings with a yellow dot. See Check the robot with Build. |
| "Build failed" in the Build panel | There is at least one error. | Press the finding with the red dot, fix the parts and press Build again. |
Startup and screen
"Builder runs on a computer" screen appears
Cause: The browser window is 900 px wide or narrower, or narrower than 1100 px on a touch device. Builder needs a mouse and a large screen.
Fix: On a computer, make the window wider or zoom the browser out. On a phone, press Send the link to my computer (or Copy link, if it is there) and open the link on a computer.
See Builder, What you need.
A panel disappeared
Cause: Someone pressed the panel's close button, or unchecked it in the View menu.
Fix: Select the panel from the PANELS group in the View menu. To put all the panels back where they started, select View > Reset layout.
See Arrange the panels.
Shortcut keys do not work
| Cause | Fix |
|---|---|
| The cursor is in a text box. | Click an empty spot in the Scene. |
| Assembly mode is on. | In the Assembly strip, press Switch to editing. |
| The Mirror or Pattern window is open. | Close the window with Esc. |
See Shortcuts.
Dragging with the left button draws a box instead of rotating the camera
Cause: The left button only selects. The camera moves with the right and middle buttons.
Fix: Drag with the right button. For other controls, select one from the MOUSE CONTROLS group in the View menu.
Adding parts and the shop
"Could not reach the shop stock - using the static catalog" appears
This notification appears while Builder is opening.
Cause: Builder could not reach the shop's live stock. You can still add parts, but the stock information is old.
Fix: Check your connection and refresh the page.
See Add parts.
"No results" appears
Cause: No part matches the text in the Search parts... box.
Fix: Type a shorter word or a product code (SKU).
See Add parts.
"The ... model did not load" appears
In place of the "...", the text shows the part's name.
Cause: The part's 3D model could not be downloaded.
Fix: Check your connection, delete the part and add it again.
See Add parts.
"The part model did not load, nothing was mirrored" appears
Cause: The model of the part you wanted to mirror could not be downloaded.
Fix: Check your connection and try Mirror again.
See Duplicate, mirror and pattern parts.
"The selection is on the mirror plane and is its own mirror, no copy needed" appears
With several parts, the text is "N parts are on the mirror plane and are their own mirror, so they were not copied".
Cause: The part sits exactly in the middle of the mirror plane. Its mirror is the same as the part.
Fix: Under Where the plane passes, select another option (such as Next to the selection).
See Duplicate, mirror and pattern parts.
"No exact mirror part for .... Placed in the closest pose, check it" appears
In place of the "...", the text shows the part's name.
Cause: The catalog has no left-right flipped twin of this part. Builder placed the part in the closest pose.
Fix: Check the copy, and fix it with Rotate if needed.
See Duplicate, mirror and pattern parts.
"Count must be between 2 and 50" or "Spacing cannot be 0" appears
A value in the Pattern window is out of range.
| Cause | Fix |
|---|---|
| "Count must be between 2 and 50": Total count is out of range. | In the Total count box, type a number from 2 to 50. |
| "Spacing cannot be 0": Spacing (mm) is 0. | In the Spacing (mm) box, type a number other than 0. |
See Duplicate, mirror and pattern parts.
"This part cannot be cut, so the hole was added as a separate Hole part" appears
Cause: In Extrude you selected Hole as the Type, but the part you opened the sketch on cannot be cut (for example a catalog part, an imported model or a Hole shape). A hole cuts basic shapes, combined shapes and Extrude parts.
Fix: The hole stays as a separate part. Delete it if you do not need it. To cut, open the sketch on a face of a basic shape, a combined shape or an Extrude part.
See Draw a sketch and make it solid with Extrude.
"Imported parts cannot be merged" or "Sketches cannot be merged" appears
In the same situation, "Select at least one solid shape to merge" can also appear. Merge works on basic shapes, combined shapes and Extrude parts. It appears when at least two parts are selected, and it needs at least one Solid shape.
| Cause | Fix |
|---|---|
| The selection has an imported part. | Take the imported parts out of the selection. |
| The selection has a sketch. | Take the sketches out of the selection. |
| The selection has no Solid shape. | Add a solid shape to the selection. |
See Make a part from basic shapes.
"A sketch opens only on a flat face" appears
Cause: You clicked a curved face for the sketch.
Fix: Click a flat face or a plane.
See Draw a sketch and make it solid with Extrude.
"The sketch has no closed region" appears
Cause: Extrude needs a closed shape. The ends of the lines do not meet.
Fix: Close the shape, or draw a rectangle or a circle.
See Draw a sketch and make it solid with Extrude.
"Extra or conflicting constraints, delete the red ones" appears
Cause: The constraints in the sketch do not agree with each other.
Fix: Delete the constraints that show in red.
See Draw a sketch and make it solid with Extrude.
Moving, Mate, Measure
"Editing is off in assembly mode. Switch to editing to make changes" appears
Cause: The robot is in assembly mode, which you started with Build step by step. In this mode you cannot move, add or delete parts. The Parts list is read-only.
Fix: In the Assembly strip, press Switch to editing.
See Build the robot step by step.
The part jumps in 2.5 mm steps or sticks to a hole
Cause: Snap is on.
Fix: Hold Shift while you move the part, or turn off Snap in the Toolbar.
"This part is being moved too. Click a part outside the selection" appears
Cause: In Mate, you clicked a target part that is also in the selection you are moving.
Fix: Click a hole on a part outside the selection.
See Mate parts by their holes.
"The target part is attached to the part being moved. Detach it in Properties first" appears
Cause: The target part is attached to the part you are moving. They move together.
Fix: Select the target part, press Detach in the Connection section of the Properties panel, then mate the part again.
See Group parts and attach them to each other.
"The back of this face was not found" appears
Cause: You pressed F to flip the part, but Builder could not find the part's opposite face.
Fix: Rotate the part with R, or mate it from another hole.
See Mate parts by their holes.
I pressed Esc and all the measurements were deleted
Cause: While Measure is on, Esc first deletes the unfinished measurement, then all the measurements.
Fix: To delete one measurement, press Delete this measurement in the Measure panel.
See Measure a distance.
I pressed Del and the part was not deleted
Cause: While Measure is on, Del deletes the last measurement, not the part.
Fix: Turn off Measure, select the part and press Del.
See Select, hide and delete parts.
Joints and motion
"This link would make a loop. A part cannot attach to a part that is attached to it" appears
Cause: The part you selected is already attached to this part.
Fix: Select another part, or press Detach first.
See Group parts and attach them to each other.
"No shared axis found" appears
The full text is "No shared axis found. For a joint, the holes of the two parts must be on the same axis, or the part must be mounted on a motor or servo shaft".
Cause: The holes of the two parts are not on the same axis.
Fix: Use Mate to mate the part to the opposite hole or to a motor shaft.
See Set up joints and try the motion.
"No gear to mesh with" or "No pulley to pair with" appears
The text goes on with "The other part needs a joint too, and the axes must be parallel".
| Cause | Fix |
|---|---|
| The driving gear or pulley has no joint. | Set up a joint on the other part first. |
| The axes of the two parts are not parallel. | Make the axes parallel. |
See Set up joints and try the motion.
"This servo's angle is not in the data, 180° assumed" appears
Cause: The servo's rotation angle is not in the catalog.
Fix: If needed, select Limited rotation and type the Min ° and Max ° values.
See Set up joints and try the motion.
"No motor or servo joint. Use Mate to put the wheel on a motor shaft" appears
Cause: There is no motor or servo joint to move in the Motion panel.
Fix: Use Mate to mate the wheel to a motor shaft. The joint is set up by itself.
See Set up joints and try the motion.
"The joints are already set up" or "Found no joints to set up" appears
Cause: Set up joints automatically found no new joints.
Fix: Set up the joint by hand in the Connection section of the Properties panel.
See Set up joints and try the motion.
Belts
"Select two pulleys for a belt" or "Both parts must be pulleys" appears
Cause: The selection does not have exactly two pulleys.
Fix: Select the two pulleys with Shift+click, then press K.
See Add a belt to two pulleys.
"The pulley axes are not parallel" appears
Cause: The pulleys face different directions.
Fix: Rotate one of the pulleys to make the axes parallel.
See Add a belt to two pulleys.
"The pulleys are not in the same plane, N mm off" appears
Cause: The pulleys are not lined up along the shaft.
Fix: Move one of the pulleys by the distance in the text.
See Add a belt to two pulleys.
"The pulleys are too close" appears
Cause: There is no room for a belt between the pulleys.
Fix: Move the pulleys farther apart.
See Add a belt to two pulleys.
"These pulleys already have a belt" appears
Cause: A belt was already added to these two pulleys.
Fix: Use the belt that is there, or delete it and add it again.
See Add a belt to two pulleys.
"The pulleys no longer fit the belt" appears
This text appears while the belt is selected: "The pulleys no longer fit the belt. ... The belt stays where it last fit".
Cause: After you added the belt, you moved or rotated one of the pulleys. The text in the middle says why (for example "The pulleys are too close" or "The pulley axes are not parallel").
Fix: Undo the pulley change (Ctrl+Z), or delete the belt and add it again.
See Add a belt to two pulleys.
Importing
"This file type is not supported. Choose STL, STEP, GLB or OBJ" appears
Cause: The file's extension is not supported.
Fix: Export the model as STL, STEP, GLB or OBJ.
See Import a 3D model.
"The file is too big. At most 25 MB" or "The file is empty" appears
Cause: The file is larger than 25 MB, or it is empty.
Fix: Simplify the model and export it again.
See Import a 3D model.
"The file could not be read. It may be damaged or incomplete" appears
Cause: The file is damaged, or it did not download completely.
Fix: Export the file again from your design program.
See Import a 3D model.
"The file has no solid model" appears
In the same situation, "The model looks flat, it has no thickness" or "The file has invalid numbers" can also appear.
Cause: The file has no solid with a thickness, or the data is damaged.
Fix: In your design program, select the solid body and export it again.
See Import a 3D model.
"GLB files with Draco compression cannot be opened. Export without compression" appears
Cause: The GLB file is compressed with Draco.
Fix: Export the GLB without compression.
See Import a 3D model.
"This GLTF depends on separate files. Export it as a single GLB" appears
Cause: The GLTF file depends on separate texture or data files.
Fix: Export the model as a single GLB file.
See Import a 3D model.
"The model could not be simplified" appears
Cause: The model has too many triangles, and simplifying it failed.
Fix: Simplify the model in your design program and export it again.
See Import a 3D model.
"The STEP reader could not start" or "The STEP reader did not load. Check your connection" appears
Cause: The STEP reader could not be downloaded to the browser.
Fix: Check your connection, refresh the page and try again.
See Import a 3D model.
"The STEP file took too long. Try a simpler model" appears
Cause: The STEP file is too complex.
Fix: Try a model with fewer parts, or an STL.
See Import a 3D model.
"The STEP file could not be read. It may be damaged or incomplete" appears
Cause: The STEP file is damaged.
Fix: Export the file again.
See Import a 3D model.
"The models of N imported parts are not in the file. Choose the file again" appears
The imported part looks like a box in the scene.
Cause: The file you opened the project from does not have this part's model data.
Fix: Select the part and press Choose the file again in the Properties panel.
See Import a 3D model.
Files and autosave
"The parts in the scene will be deleted. Start a new project?" appears
Cause: You selected File > New while there were parts in the scene.
Fix: If you want to keep your work, cancel. Then select File > Save (download JSON) before you start a new project.
See Save to a file and open it.
"Could not read the project file" appears
Cause: The file you selected is not a Builder project file, it is damaged, or all the parts in it are damaged. A file saved with an empty scene does not show this text. It opens with an empty scene.
Fix: Select another .json copy that you downloaded with File > Save (download JSON).
See Save to a file and open it.
"N damaged parts were skipped" appears
Cause: The data of some parts in the file could not be read. The rest of the project opened.
Fix: Add the missing parts again and save the project again.
See Save to a file and open it.
"Autosave failed" appears
When the storage is full, the text is "Autosave failed because the browser storage is full".
Cause: The browser could not keep your work.
Fix: So you do not lose your work, select File > Save (download JSON).
See Save to a file and open it.
"The autosave could not fit the imported models" appears
The text goes on with "Download the project with Save in the File menu".
Cause: The imported models are too big to keep in the browser.
Fix: Select File > Save (download JSON). The models are embedded in the file.
See Save to a file and open it.
"The models of N imported parts are not in the autosave. Choose the file again" appears
This text appears when you open the page again.
Cause: The autosave could not keep these models.
Fix: Select the part and press Choose the file again in the Properties panel.
See Import a 3D model.
Account and sharing
"Connecting" or "Not available right now" appears
The account items in the File menu look faded, with one of these texts next to them.
| Cause | Fix |
|---|---|
| "Connecting": Builder is connecting to the account server. | Wait a little. |
| "Not available right now": The server could not be reached. | Refresh the page. In the meantime, save with File > Save (download JSON). |
See Save to your account and share.
"Sign in to .... Your robot stays in this tab." appears
Cause: You are not signed in to your Probot account.
Fix: Press Sign in in a new tab and sign in (the sign-in page is in Turkish). Then come back to this tab and try again.
See Save to your account and share.
"There must be at least one part in the scene to save" appears
In the same situation, "There are no parts in the scene. Build your robot first, then save." can also appear.
Cause: The scene is empty.
Fix: Add parts or load a ready-made robot.
See Start with a ready-made robot.
"The robot is X MB, at most Y MB can be saved" appears
The text goes on with "Use fewer imported models and try again". In the same situation, "The robot is too big to send to the server. Use fewer imported models and try again" can also appear.
Cause: The robot is bigger than what can be saved to an account. Imported models are usually what make it big.
Fix: Delete or simplify the imported models. Save the robot to a file with File > Save (download JSON).
See Save to your account and share.
"Could not reach the server. Check your connection and try again" appears
In the same situation, "The server is not responding right now. Try again in a little while" or "The server sent an unexpected response" can also appear.
Cause: The account server could not be reached.
Fix: Check your connection and try again in a little while.
See Save to your account and share.
"Çok hızlı istek yapıldı. Bir dakika sonra tekrar dene." (Too many requests too fast) appears
The server sends this message in Turkish only (Too many requests too fast. Try again in a minute.). If the server sends no message, Builder shows "Too many requests. Try again in a minute".
Cause: Too many requests were sent in a short time.
Fix: Wait one minute and try again.
See Save to your account and share.
"To create a link, save the robot to your account first." appears
Cause: The robot is not saved to your account yet.
Fix: First select File > Save to my account....
See Save to your account and share.
"The link shows the last saved version" appears
The text goes on with "Save again to show your changes."
Cause: You changed the robot after you saved it. The link shows the old version.
Fix: Save again with File > Save to my account....
See Save to your account and share.
"Link selected, press Ctrl+C to copy" appears
Cause: The browser did not allow writing to the clipboard.
Fix: Press Ctrl+C.
See Save to your account and share.
"Could not open the shared robot" appears
In the same situation, "This share link is turned off or was not found" or "Robot bulunamadı" (Robot not found, a server message in Turkish) can also appear.
Cause: The link was turned off, the robot was deleted, or the link is wrong.
Fix: Ask the person who sent you the link for a new link.
See Save to your account and share.
"Imported parts cannot be shared in the catalog. Remove them first" appears
Cause: The community catalog does not accept imported models.
Fix: Delete the imported parts, then press Share in the form again.
See Save to your account and share.
"Could not share the robot" or "The request could not be completed" appears
Cause: The share request could not be completed on the server.
Fix: Try again in a little while.
See Save to your account and share.
"Could not load community robots" appears
This text appears in the Robot catalog.
Cause: The community list could not be loaded from the server.
Fix: Press Try again.
See Start with a ready-made robot.
"Could not load the robot" appears
This text appears when you open a community robot.
Cause: The robot's file could not be loaded or read.
Fix: Try again in a little while, or select another robot.
See Start with a ready-made robot.
Make it real and the robot check
"No parts in the scene - design your robot first" appears
Cause: The scene is empty.
Fix: Add parts or load a ready-made robot.
See Make it real: send the parts list to the shop cart.
"No Control Hub", "No battery" or "No power switch" appears
Cause: The robot is missing a required electronic part that FTC asks for.
Fix: Press Add the missing parts, then move the parts that appear onto the robot.
See Make it real: send the parts list to the shop cart.
"The robot has N motors, the limit is 8" or "The robot has N servos, the limit is 8" appears
Cause: The robot has more than 8 motors or servos.
Fix: Press show, then delete the extra motor or servo.
See Make it real: send the parts list to the shop cart.
"At the start the robot is N mm too ..., the limit is 18 in" appears
Cause: The robot is bigger than 18 inches (457.2 mm) in one direction.
Fix: Press show, then move the parts at the edge inward or make them shorter.
See Make it real: send the parts list to the shop cart.
"... is not attached to the robot" appears
Cause: Some parts do not touch the rest of the robot.
Fix: Press show, then move the parts to the robot or mate them to it.
See Mate parts by their holes.
"Could not reach shop prices right now" appears
The text goes on with "the list is shown, but adding to the cart is off. Try again in a moment."
Cause: The shop's prices could not be loaded.
Fix: Close the window and open it again in a little while.
See Make it real: send the parts list to the shop cart.
"Could not add the parts to the cart. Your current cart is unchanged. Try again." appears
Cause: Adding to the cart stopped partway. Your cart in the shop did not change.
Fix: Press Add to cart and go to the shop again.
See Make it real: send the parts list to the shop cart.
"Some part models could not be loaded" appears
Cause: A part model could not be downloaded during Add the missing parts.
Fix: Check your connection. Then close the window and open it again to repeat the robot check.
See Make it real: send the parts list to the shop cart.
A part does not go to the cart
Cause: The UNIT PRICE column shows "price coming soon", "out of stock" or "N in stock".
Fix: Keep track of this part in the shop separately (the shop is in Turkish).
See Make it real: send the parts list to the shop cart.
Build
"Build failed" appears
Cause: The findings have at least one error (for example "overlap").
Fix: Press the finding with the red dot, fix the parts and press Build again.
See Check the robot with Build.
"The scene is empty - there are no parts to build." appears
Cause: There are no material parts in the scene.
Fix: Add parts or load a ready-made robot.
See Check the robot with Build.
"Separate group: ... - not connected to the main structure." appears
In the same situation, "No bolted connections - the parts are only resting on each other." can also appear.
Cause: The parts do not touch each other, or their holes are not lined up.
Fix: Use Mate to join the parts by their holes.
See Mate parts by their holes.
"No motor shaft on the axis of N wheel(s)." appears
In the same situation, "There are wheels but no motor - the robot cannot move." can also appear.
Cause: There is no motor to turn the wheel.
Fix: Add a motor and mate the wheel to its shaft.
See Set up joints and try the motion.
I fixed the robot but the result did not change
Cause: The Build result does not refresh by itself.
Fix: Press Build again.
See Check the robot with Build.
Sim
Try in Sim is faded
Cause: The scene is empty.
Fix: Load a robot.
See Try the robot in Sim.
Try in Sim is missing from the menu and the Robot catalog
Cause: Sim is not responding at this address. Builder shows the item only while Sim can be reached.
Fix: Refresh the page. If the problem goes on, save the project to a file.
See Try the robot in Sim.
I pressed Try in Sim and no new tab opened
Cause: The browser blocked the pop-up window.
Fix: Use the blocked pop-up icon in the address bar to allow this site, then press Try in Sim again.
See Try the robot in Sim.
Report a bug
If you cannot find your problem on this page, you can write to the team without leaving Builder. The 🐛 Report a bug button is in the Site header, next to the "BUILDER" badge. While the "The design tool is in development" window from startup is open, an arrow points to this button with the text "The Report a bug button is always here".
- In the Site header, press 🐛 Report a bug. If the intro window is still open, press 🐛 Report a bug in that window.
- In the Title box, type a short summary of what happened.
- In the Message box, type the items in the list below.
- Press Send. To cancel, press Cancel.
Result: The window shows "Received, thank you! 🎉". Press Close to close the window. If sending fails, "Could not send it. Try again or use the Contact page." appears.
Write these in the message:
- The open robot or the project name, for example "Omni chassis" or the project name in the Toolbar.
- The last button or key you pressed.
- The text on the screen, word for word, in quotes.
- Your browser, for example Chrome.