# Is there any good solution about the accuracy issue caused by scaling?

**URL:** <https://forums.sketchup.com/t/is-there-any-good-solution-about-the-accuracy-issue-caused-by-scaling/339079>\
**Category:** Ruby API\
**Tags:** sketchup\
**Created:** [August 20, 2025, 9:03am UTC](https://forums.sketchup.com/t/is-there-any-good-solution-about-the-accuracy-issue-caused-by-scaling/339079 "2025-08-20T09:03:53Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![javalitterboy](https://sea2.discourse-cdn.com/sketchup/user_avatar/forums.sketchup.com/javalitterboy/32/170896_2.png) [@javalitterboy](https://forums.sketchup.com/u/javalitterboy)\
**Post date:** [August 20, 2025, 9:03am UTC](https://forums.sketchup.com/t/is-there-any-good-solution-about-the-accuracy-issue-caused-by-scaling/339079/1 "2025-08-20T09:03:53Z")

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```ruby
tr_arr = [4.8364636603358906e-09, 1.377460047609002e-11, 0.018500680967125094, 0.0, 0.026387430624252976, 7.515328429044587e-05, -3.3909277664520265e-09, 0.0, -5.166779173874384e-05, 0.04901591274040792, -4.2722038991268865e-17, 0.0, 8509.194934285286, -19763.790146299514, -478.77437297581986, 1.0]
trans = Geom::Transformation.new(tr_arr)
plane1 = [Geom::Point3d.new(0, 6905.33, 0), Geom::Vector3d.new(-0, -1, -0)]
plane2 = [Geom::Point3d.new(7721.26, 6905.33, 0), Geom::Vector3d.new(-0, -1, -0)]

puts "same:#{plane1[1].samedirection?(plane2[1])} dis:#{plane1[0].distance_to_plane(plane2)}"

plane1.map! { |pt| pt.transform(trans.inverse) }
plane2.map! { |pt| pt.transform(trans.inverse) }

puts "same:#{plane1[1].samedirection?(plane2[1])} dis:#{plane1[0].distance_to_plane(plane2)}"

```

```plaintext
same:true dis:0.0
same:true dis:124.30154003680218

```

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<div class="post-metadata">

**Author:** ![sWilliams](https://avatars.discourse-cdn.com/v4/letter/s/838e76/32.png) [@sWilliams](https://forums.sketchup.com/u/sWilliams)\
**Post date:** [August 21, 2025, 8:53pm UTC](https://forums.sketchup.com/t/is-there-any-good-solution-about-the-accuracy-issue-caused-by-scaling/339079/2 "2025-08-21T20:53:46Z")

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It appears that the transformation matrix is ever so slightly non-orthogonal; i.e. the axes of the transformation are not perpendicular to each other. This results in a systematic skewing of the points and planes that are being calculated. How was the transformation created?

Here’s a bit of code showing the details.

[Inspect transformation.rb](https://forums.sketchup.com/uploads/short-url/tEAmIy1BOPFNymY3RCMfM0obpe4.rb) (1.1 KB)

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<div class="post-metadata">

**Author:** ![javalitterboy](https://sea2.discourse-cdn.com/sketchup/user_avatar/forums.sketchup.com/javalitterboy/32/170896_2.png) [@javalitterboy](https://forums.sketchup.com/u/javalitterboy)\
**Post date:** [August 26, 2025, 12:59am UTC](https://forums.sketchup.com/t/is-there-any-good-solution-about-the-accuracy-issue-caused-by-scaling/339079/3 "2025-08-26T00:59:07Z")

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I cannot confirm how it occurred; it may have been caused by the imported third-party model

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**Author:** ![system](https://global.discourse-cdn.com/sketchup/original/3X/f/2/f2a121500b085ed60806607a82720b092d800bb3.png) [@system](https://forums.sketchup.com/u/system)\
**Post date:** [September 2, 2025, 12:59am UTC](https://forums.sketchup.com/t/is-there-any-good-solution-about-the-accuracy-issue-caused-by-scaling/339079/4 "2025-09-02T00:59:08Z")

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