Scale

Scale on export seems incorrect. I created points and defined a distance constraint before alignment. After reconstruction, the component shows it is using 1 constraint. When a model is exported to OBJ or PLY, the scale is wrong. I tried updating and realigning again, but the scale is still wrong. The coordinates in the OBJ are not what would be expected if the scale were in the units I entered for the distance , so I don’t think this is a problem on the side of the other software (Meshlab). How can I get scale to work?

Hi Adam Rountrey

Can you make a screenshot of the EXPORT settings for PLY/OBJ?

For the proper scale in an external application, as we have observed many times, you need to figure it out by testing what units need to be set so that the scale is PROPERLY imported. If you remember, someone has already mentioned issues with Meshlab + few other sw solutions.

Is it possible to send me, say, a 1 mil triangle model so that I can check it in Geomagic?
Please send it to milos.lukac@capturingreality.com

If you set scale bars properly and then align, the scale is set properly, as we have tested it many times…

Thank you for the quick reply.
Yes. I will send model tomorrow. The coordinates in the OBJ (opened with a text editor) are too small (all with absolute value less than 2) to represent the distance I put in as a constraint (81.87 units).

Untitled.jpg

Hi Adam Rountrey

OK, send it…

And try changing PRESERVE COORDINATES to FALSE in the meantime…

Hi Adam Rountrey

Reading your email, you need to set the scale to mm but RC default units are meters.
So your scale constraint needs to be set to meters -> 0.08187 and not 81.87.

When you change a constraint, you need to realign and reconstruct the model or change the import units in Meshlab to mm.
But if you have used UPDATE in between, I highly recommend you to realign and reconstruct the model…

I set the constraint distance to 0.08187, realigned, and reconstructed. The resulting exported model has the same scale as the one produced when scale was 81.87. I also tried changing “Preserve Coordinates”, but I get the same result both ways.

Thank you for your continued help on this problem.

Hi Adam Rountrey

Please read the email with screenshots for confirmation on the issue.

Any solution to this?

I just tested on latest RC (1.0.2.1978). I set distance between two control points as 100, aligned, built mesh, exported as mesh1, then changed the distance to 10000, aligned again, built mesh, exported as mesh2. After import to 3rd party app (Unreal in my case), both meshes show identical scale.

-Andrew

Hi Andrzej,
thanks for reporting we will check it.

Hi I have this problem too, posted in Bug reports

Was wondering if there was any news on this?

Would it be easy to roll back to a previous version of CR before the update?

Thanks

Any further action on this? i am getting the same problem…

scale set to 0.53, aligned and exported and scale is wrong in Autodesk Recap. Changed distance to 0.0053, aligned and exported and the scale is the same as when it was exported the first time…?

Unfortunately, I am having a scaling problem too. I am using laser scan data and images.

I cannot seem to find the “preserve coordinates” check box, often referred to in previous posts, has it been removed?

I am having trouble with this as well. RC seems to ignore scale when exporting to mesh. I have tried both coordinates and tie points methods. Any news on this front?

Hi all
When you use just images and set scale using control points, then you need to REalign the scene so that it’s included in the project. when you don’t do this, then the scale is NOT applied and you won’t get proper scale
If you use data from laser scanners, then the SCALE is set properly, as laser scanners always export in metric scale ( or imperial depending on your laser scanner software settings )
If you still have issues, please make a proper report on your workflows so that we can find the issue and correct it…

I apologize for my short post. I wanted to see if this was a common issue before writing a in depth explanation.

Setup
Image
I have 4 markers on the floor 1 meter apart from each other.
I am considering z as up.
Coordinate system set at Local:1-Euclidean.
Applications used for measurements = Rhino & meshmixer
Camera: Iphone 6S

Workflow 1 (TP)
TP - CP’s & distances placed before alignment.

  1. Set CP (Type: Tie Points). point 0 and point 2. Minimum 4 images per each point.
  2. Define distance between points 0 and 2 as 1 meter.
  3. Align.
    Continue rest of workflow

Workflow 2 (TP)
1-3 same as workflow 1
4. update
continue rest of workflow

Workflow 3 (GCP)

  1. Set GCP Point 0 - 4. Minimum 4 images per each point.
  2. Set Type to Ground Control
  3. Input coordinates (show in image)
  4. Align
    Continue rest of workflow

I have tried all 3 and none of them are producing the correct scale. Also when using GCP’s the orientation of the model comes out incorrect. Am I doing something wrong?

Also, I saw in another post that RAD markers might be in the pipeline. Any news on that? Thank you.

Hi Sung
I don’t have experience with Rhino or Meshmixer, but from other sw packages we know there’re some issues regarding PROPER scale import. 3Ds max is working, Maya is working and other sw, too… in Maya you need to set it from cm to M and it’s working properly…

When you use Workflow 1 and 3, then it’s WORKING, as we’ve tested it many times.

Look for import settings in the software you use, if you can eventually change units for imported files.
I’ve even seen that you need to set CM to get proper scale in METERS, which are our units…

I’m having a similar scale issue, but with orthophotos.
Workflow was as follows:

  1. Align images
  2. Mark 4 control points (each control point is picked in 4 pictures, they are points on a scale bar)
  3. Create 2 distances between these control points as constraints
  4. Update

I haven’t checked whether the actual 3D model is to scale after export, but at least when I open the ortho view in RC the “unit bar” at the top of the view is way off, and doesn’t seem to have adapted after clicking “Update”.

Hi Thomas Van Damm

  1. Align images
  2. Mark 4 control points (each control point is picked in 4 pictures, they are points on a scale bar)
  3. Create 2 distances between these control points as constraints
  1. ALIGN again to get correct scale etc.

You need to use ALIGN again so that the constants are included in alignment solution, the UPDATE is used when you have set everything properly and need to change the PROJECTION SYSTEM, it is not set for setting proper scale…

Just a side note - it is supposed to work like this: The Update option changes solely the coordinate system of the currently selected component and it also updates the scale of all children models, whereas the Align Images (F6) button creates a new component.