{"id":12497,"date":"2022-09-04T16:26:22","date_gmt":"2022-09-04T15:26:22","guid":{"rendered":"http:\/\/www.keris-studio.fr\/blog\/?p=12497"},"modified":"2022-10-08T17:15:55","modified_gmt":"2022-10-08T16:15:55","slug":"the-old-tree-photogrammetry","status":"publish","type":"post","link":"https:\/\/www.keris-studio.fr\/blog\/?p=12497","title":{"rendered":"The old Tree – photogrammetry"},"content":{"rendered":"

A tree is not an obvious subject to scan. For this test, it\u2019s even more complicated as it has no leafs left, and very thin branches. Let\u2019s see what we can get. Let’s see what we can do.<\/p>\n

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<\/p>\n

From Photos to 3D<\/h1>\n

We have a selection of 190 photos, taken from the ground, some will not be used.<\/p>\n

<\/p>\n

In Metashape<\/a><\/strong>, we import our 186 usable photos.<\/p>\n

Workflow \/ Add Photos<\/strong><\/p>\n

<\/p>\n

Then Workflow \/ Align Photos<\/strong><\/p>\n

We get a very nice and delicate PointCloud with 96935 points<\/p>\n

<\/p>\n

Then we calculate the dense cloud : WorkFlow \/ Build Dense Cloud<\/strong><\/p>\n

It results a PointCloud with 45\u00a0195\u00a0055 points.<\/p>\n

<\/p>\n

For more detail about the workflow, refer to any of these tutorials : https:\/\/www.keris-studio.fr\/blog\/?p=11270<\/a> or https:\/\/www.keris-studio.fr\/blog\/?p=1185<\/a>1 or https:\/\/www.keris-studio.fr\/blog\/?p=12084<\/a><\/p>\n

The bleu dots are pieces of sky that are incorporated. We can try to remove them with colour filtering. First we duplicate (just in case) \"\"<\/a><\/p>\n

Dense Cloud \/ Dense Cloud \/ Select Points by Color<\/strong><\/p>\n

Use color picker to have the correct color code.<\/p>\n

\"\"<\/a><\/p>\n

Delete what have been selected<\/p>\n

<\/p>\n

Nearly all my blue points are selected<\/p>\n

<\/p>\n

I can remove them, I do a second pass with a lighter colour<\/p>\n

<\/p>\n

It\u2019s done.<\/p>\n

Meshing<\/h1>\n

The meshing will give poor results. Let\u2019s test it<\/p>\n

<\/p>\n

Poor tree, nothing much left<\/p>\n

<\/p>\n

https:\/\/skfb.ly\/owF6J<\/a><\/p>\n

The Point Cloud remains very nice, and could be used as it.<\/p>\n

<\/p>\n

We might be able to do better.<\/p>\n

\"\"<\/a><\/p>\n

Decimation<\/h1>\n

First let\u2019s create several resolutions for our PointCloud
\nIn Metashape go to Tools\/Dense Cloud \/ Sample Points<\/strong><\/p>\n

<\/p>\n

It gives a nice Point Cloud<\/p>\n

<\/p>\n

To remesh it, we have to use another tool.<\/p>\n

So first, we shall export the points<\/p>\n

Right Click on the Dense Cloud Point :<\/p>\n

\"\"<\/a><\/p>\n

When done, the Points can be exported in PLY to be reworked everywhere.<\/p>\n

Meshlab<\/h1>\n

Meshlab is a free software, we will remesh the point with it. https:\/\/www.meshlab.net\/<\/p>\n

Import the PLY file with file\/Import Mesh<\/strong><\/p>\n

Then apply the Ball pivoting filter<\/p>\n

<\/p>\n

For now leave presets as they are<\/p>\n

Enjoy the result in Sketchfab<\/p>\n