Accurately measure dimensions with 1% error rate

At a 65’ (20 meters) range, the Visual Plan Software can achieve +/- 1%-dimensional measurement error rate so long as the setup and workflow is completed correctly.

Since Visual Plan uses photogrammetry processing, the most important part of the workflow is the determine the correct absolute scale for each section. Without this, its not possible to measure absolute distance.

Photogrammetry processing has a hard time distinguishing these two sets of camera positions because they can generate exactly same photos.

DISCLAIMER: To make things visually proportional during processing, our software makes some assumptions. The tool is intended for visualization and planning. It is not intended to meet dimensional guidelines or meet regulations of high accuracy

3 Methods to calculate absolute scale

1 .Markers – automatic and the most accurate method (download here).

How Too:
Place market sheet into scene when photographing to automate the scaling step for higher accuracy. The Visual Plan software will automatically recognize the markets and calibrate the scale. Use scale status Scaled by auto-detection markers

Use a known dimension

1. Measure a dimension that you know the real value using measure button available in the Editor toolbar.

2. Right mouse click on the dimension and select Scale menu, and enter the real value you have recorded.

Average camera height - the easiest method to estimate

In absence of markers or reference dimensions, you can scale a section by using the estimated average camera height with reasonable accuracy. You will need two pieces of information to ensure this works before setting the camera height value.

• Floor Position
The floor is the vertical origin of a section in the 3D space and can be easily adjusted by clicking the Adjust Floor button and picking a common floor point from two different panos. It is rendered in a blue plane in 3D mode.

Current Pano was Taken on the Floor
This would imply that the image you are viewing in the Editor has been taken on the floor. Our software will try to detect if the image was taken from the floor using a few assumptions, but it may not be correct, so you can correct this at any time. If the information is incorrect, the scale factor calculated using camera height would also be wrong.

At this point, we are prepared to use the approximate average height from the ground, orienting the lens center in the Adjust Section interface, giving you an estimated scale.

Select a common point from 2 panos

You may select a 3D point by selecting the same point in two different images. Although there is some human error when selecting a pixel, the method is pretty accurate. A grey baseline will appear in the corresponding pano after you have selected a point in one of the panos. This will indicate that the pixel should be along this baseline. You can then use your mouse pointer to auto snap to this baseline for ease of selection allowing you to select 3D points from any surface, even without any underlying 3D data, with reasonable accuracy.

Pick a point on the floor

Another method to select a point is to select a point from the floor. A floor is an infinite plane even if it is rendered by a plane with bounds. This option is useful when you measure dimensions for floor plan generation.

Pick a point on 3D boxes

You may also select points on 3D boxes. This method is useful when you know where to locate reference 3D boxes.

Pick a point on 3D mesh

You must have an underlying 3D mesh to use this method. When the geometry of a wall is well generated, and you want to measure wall-to-wall distances (rather than point-to-point), you should use this method. The easiest way to check the quality of the 3D mesh geometry is to make sure wall-lines of the auto-generated blue sketch in the Layout tab look clear and correct.

Factors impacting measurement accuracy

There are other factors other than scale that can impact accuracy.

• Photo quality
360 camera vendors use different parameters when stitching photos from multiple fisheye (or wide-angle) lenses, and they may make an effect on our photo positioning accuracy. The best cameras in this regard are Ricoh Theta V, Insta360, MadVenture 360, Yi 360 at the time of writing.

• Enough overlap among 360 photos
Our server processing primarily relies on the common image areas among photos, and therefore enough overlap is also vital to achieve the reliable result.

LEARN MORE HERE

Eyeballing when picking a point
You should expect a human error like when you use a tape measure or other measuring devices. Again Common Point from 2 Panos would be the best option to minimize this point-picking inaccuracy

Measure dimensions with Visual Plan Web Player

You Enable Measure in the Visual Plan Web Player so viewers or workspace users with the Review-Only permission can measure dimensions. This is found in the Customize Player menu.

Review Table to Measure, Save and Delete dimensions

When Enable Measure is switched on as above, you can measure, save and delete dimensions in the Review tab as well. Only thing to keep in mind is that if you are “Review-only” member, then you are allowed to delete only the ones that you measured, whereas edit-authority will allow measuring and deleting all.
Here’s how,

1. Toggle on the Enable Measure in the Publisher tab’s Customize Player options
2. Go to Review tab and click Measure Dimensions in the upper left corner of the screen.

3. You will have a measuring option window pop up on the right hand side

 
4. To delete, simply select the dimension and press “delete” key.

• Common Point from 2 Panos: It is triangulation method that you need to chooose two common points from each two panos’ view to measure.
• On the Floor: You need to pick two points on a floor (a plane) to measure distance between the two.
• On 3D Mesh: A measurement will occur on top of the 3D mesh.
• Snap on Ends of Other Dimensions: While measuring a dimension that shares a point with a previously measured dimension, the measuring bar will automatically snap on to the existing endpoint.
• Axis Aligned Dimension: The measuring bar will only follow x and y axis.