I need higher accuracy than 1-2%. Can I submit my own dimensions to improve accuracy?

The Short Answer

On its own, Canvas will typically yield accuracy tolerances (most measurements within ~1-2%) sufficient for design, pricing, planning, and estimating and you can read about expected tolerances here: What kind of accuracy can I expect from Canvas?

If you have specific accuracy tolerances such as all measurements within 1/16", or 1mm, we can accept your field measurements to include in your order. This means your file will contain (where provided) your field measurements, and the scan will provide the rest. 

To submit your dimensions, email our support team at support@canvas.io with your documents and referencing your order ID.

The Long Answer

For certain kinds of construction and installation work (such as installing cabinets), you may need tolerances that are within 1/16" or within 1mm (even on long distances), and that kind of precision is unfortunately going to be difficult for mobile 3D scanning in general (Canvas or any other kind, even at much higher price points). 

In order to help you get a model that includes these tight tolerances, you can submit a drawing or diagram with any manually verified dimensions with your Scan To CAD order. Then, we will override the existing values for those dimensions with the measurements you provide and use the scan to process everything else. This means that the model you receive from Scan To CAD will use your verified dimensions for anything provided (for better or worse!), and rely on the scan for any dimensions that are not provided. 

In this way, you get the best of both worlds — you can rely on the scan for all the dimensions where our expected tolerances are acceptable and include manual dimensions for the (typically much smaller) number of dimensions that demand higher precision. 

Scaling

Provided dimensions are not used to scale the rest of the model and are instead solely used to override the information from the scan. Essentially, with mobile 3D scanning, the tiny amount of error that builds up is mostly random, so scaling an entire scan from some measurements would require making assumptions about the rest of the scan (specifically that the error is all the same).

How To Submit A Drawing With Manual Measurements

When submitting a drawing with manual measurements, please follow these guidelines:

  • Your verified dimensions must be annotated in clear and legible text or handwriting, using English characters. 
  • Imperial or metric units are both acceptable.
  • The start and endpoint for any dimension must be clear and unambiguous from the drawing, and not rely on "industry-standard" assumptions (e.g., does a door opening dimension include the casing around it or not - these vary significantly across industries).
  • Send your drawing as an image or PDF — if you send a .dwg file it may require additional time to triage.
  • A digital drawing is preferred, but a photo of a hand drawing is also acceptable if the photo is clear and readable. 
  • Include the order ID in the subject line and send to support@canvas.io as soon as possible after you upload your scans.

Here is an example of a totally acceptable drawing submitted by a customer with their order as extra reference: 

It's not fancy, but it gets the job done, and we were able to match the dimensions provided in the final CAD model. 

Important: Drawings are subject to significant human interpretation, and may from time to require clarification that can delay your order. It is also still completely possible for us to miscommunicate or misinterpret certain dimensions, especially given that it is very common for people to use shorthand abbreviations or heuristics without realizing it. While we always will make our best effort to bridge the gap with you, we can not guarantee that all dimensions will precisely match, and we recommend that you verify that the critical dimensions match your expectations when using this process.