Does a failed render use one of my tokens?

No. A token is charged only when the 3D scene completes. A failed render costs nothing, although you need at least one token in your balance to start a render.

Where can I see why a scan failed?

On your dashboard, next to the upload. Rooms in a property tour also show the reason in the tour's room list, with a Record again button.

Can I tell whether a clip will work before uploading it?

Partly. After a guided room capture, WalkTortoise shows a capture report with the moves completed, the sideways movement, the share of sharp frames and the steps taken, and suggests re-recording when the clip looks weak. It cannot spot everything, such as a person walking through the shot.

Why was my video rejected as too long or too large?

Regular accounts can upload videos of up to 60 seconds and 500 MB. Trim or compress the file, or re-record a shorter clip that follows the guided moves.

Guide

Why 3D Room Scans Fail and How to Fix Them

Updated October 27, 2026

Most failed 3D room scans come down to how the clip was filmed: turning on the spot instead of moving sideways, motion blur, low light, mirrors, glass or blank walls, people or pets moving, or a clip that is too short. Each one stops the software from working out where the camera was, or from matching the room between frames. The fix is to re-record slowly in bright light with real side-to-side movement, and on WalkTortoise a failed render costs no token.

Turning on the spot instead of moving sideways

This is the most common cause. Depth comes from seeing the same object from different positions, and a phone that only rotates sees everything from one point. WalkTortoise catches this early and stops with a message such as 'Camera tracking failed' or 'Almost no camera movement detected'. Walking straight in from the door has a similar problem and can end with 'Reconstruction too sparse'.

Fix: side-step slowly along an arc, walk across the room, then arc back the other way, as the guided capture shows. After a guided capture, the capture report warns you before upload when the clip has very little sideways movement.

Motion blur

Blurred frames hide the fine detail that is matched between frames, so they are removed before the scene is built. With too many of them there is not enough left to work with, or the scene comes out as floating fragments instead of solid surfaces.

Fix: move slower, take small steps and hold the phone steady. More light helps too, because the camera can use a faster shutter. The camera screen says 'Hold steadier' while you film, and the capture report flags clips where more than a quarter of the frames are blurred.

Low light

Dark frames carry little usable detail, especially in corners, so the scene can fail or come out with gaps. The camera screen shows a 'Too dark' warning, and the capture report flags clips where much of the footage is too dark.

Fix: switch on every light, open the blinds and avoid aiming at bright, backlit windows, which leave the rest of the frame dark.

Mirrors, glass and blank walls

Reconstruction relies on spotting the same details from different angles. A mirror or a pane of glass shows a different picture from every angle, and a plain wall has almost no detail to spot. WalkTortoise's own guidance is to avoid shiny or reflective surfaces and blank, textureless walls.

Fix: film past mirrors rather than straight into them, keep furniture, edges and doorways in frame next to plain walls, and stay one to two metres from the walls.

People or pets moving

The method assumes the room holds still while you film. A person walking through the shot, or a pet moving around, is in a different place in every frame, so it cannot be matched and tends to leave ghosts or floating fragments.

Fix: clear the room before you start and close the door behind you.

A clip that is too short

Processing takes about six frames from every second of video and needs enough sharp, overlapping ones to work with. Very short clips do not have them, and the error messages advise recording at least 15 seconds.

Fix: complete all the guided moves. Finish unlocks after 20 seconds and a normal room takes about 40. Stay under 60 seconds, the upload limit for regular accounts.

What a failed scan costs

Nothing. WalkTortoise checks that you have at least one token before a render starts, but only charges it when the 3D scene is finished. If processing fails, the token stays in your balance and the dashboard shows the reason, so you can re-record the room with the fix in mind.

Common questions

Does a failed render use one of my tokens?: No. A token is charged only when the 3D scene completes. A failed render costs nothing, although you need at least one token in your balance to start a render.
Where can I see why a scan failed?: On your dashboard, next to the upload. Rooms in a property tour also show the reason in the tour's room list, with a Record again button.
Can I tell whether a clip will work before uploading it?: Partly. After a guided room capture, WalkTortoise shows a capture report with the moves completed, the sideways movement, the share of sharp frames and the steps taken, and suggests re-recording when the clip looks weak. It cannot spot everything, such as a person walking through the shot.
Why was my video rejected as too long or too large?: Regular accounts can upload videos of up to 60 seconds and 500 MB. Trim or compress the file, or re-record a shorter clip that follows the guided moves.

Related guides

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