{"id":12461,"date":"2022-08-02T12:03:41","date_gmt":"2022-08-02T11:03:41","guid":{"rendered":"http:\/\/www.keris-studio.fr\/blog\/?p=12461"},"modified":"2022-10-08T17:17:35","modified_gmt":"2022-10-08T16:17:35","slug":"ply-importer-for-grasshopper","status":"publish","type":"post","link":"https:\/\/www.keris-studio.fr\/blog\/?p=12461","title":{"rendered":"PLY importer for Grasshopper"},"content":{"rendered":"

Tree to PLY<\/h1>\n

It can be useful to use cloudpoints in Grasshopper and therefore having a way import PLY files.<\/p>\n

The Binari format is fully readable, meaning that it\u2019s possible to read, filter, and extract any useful information. Let\u2019s dive.<\/p>\n

We will start from the photogrammetry from a tree. To test we will use a light version of the cloud point.<\/p>\n

<\/p>\n

Exporting PLY from Meshlab \/ CloudCompare<\/h1>\n

First the more important is to understand the PLY\u2019s file header. It can be slightly different depending which software writes it.<\/p>\n

Meshlab<\/h2>\n

Meshlab<\/a> <\/strong>(https:\/\/www.meshlab.net\/<\/a>) is a free software that allows to convert, manipulate and transform many 3D files format. A must have. Exporting PLY from Meshlab give this:<\/p>\n

<\/p>\n

We can here remember that the Header takes 17 lines and points coordinates are lines 5 to 6 and colour + alpha are lines 11 to 14.<\/p>\n

After the header we have the points coordinates<\/p>\n

CloudCompare<\/h2>\n

CloudCompare<\/strong><\/a> (https:\/\/www.danielgm.net\/cc\/<\/a>) is another great tool to edit, simplify, transform and export CloudPoints<\/p>\n

In CloudCompare it is possible to filter the needed information when importing<\/p>\n

<\/p>\n

The Alpha Channel is not always set. I can be done by hand.<\/p>\n

The export gives<\/p>\n

<\/p>\n

We see here that elements are not sorted in the same order. Lines 6 to 8 are for the coordinates and colours are 9 to 11 and there is no Alpha.<\/p>\n

We will take that into account in Grasshopper.<\/p>\n

Grasshopper<\/h1>\n

Let\u2019s start by creating a File Path and a Read File<\/p>\n

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Adding a Panel I can see how my file is structured<\/p>\n

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Then I will separate the Header from the points coordinates<\/p>\n

I use a Split List. Here it has to be cut line 15.<\/p>\n

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Now I need to break the lines of coordinates to have Points Coordinates, Normals, and Colors into lists.<\/p>\n

I use a Text Split<\/p>\n

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Now I\u2019ve a got my list of points and as sub lists, all the coordinates.<\/p>\n

I\u2019ll isolate the point coordinates, the colours and Normals<\/p>\n

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We add the Index and the Construct Point<\/p>\n

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For the Colours I kept the Alpha just in case, even if I don\u2019t have it here.<\/p>\n

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With Index<\/p>\n

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And Normals<\/p>\n

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Results<\/p>\n

We can see that the cloudpoint is visible in Rhino (I used a very light cloudpoint)<\/p>\n

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We can create boxes from the points to visualise the colours.<\/p>\n

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And add colours<\/p>\n

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And Normals<\/p>\n

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The definition<\/h1>\n

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Result with 10\u00a0000 points. But very fast Rhino and Grasshopper will be overflowed.<\/p>\n

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