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Author Topic: Reducing Model Size - Maintaining Accuracy  (Read 7566 times)

davidsumner

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Reducing Model Size - Maintaining Accuracy
« on: August 24, 2017, 07:35:53 PM »
This may be a topic covered else where but i was wondering if anyone has strategies for exporting models to an autocad / c3d format.  I'm able to export ok but the files size has been 1-3gbs.   I was also able to open in it acad but unable to manipulate it at this size.  Our client was unable to even open it.   Any thoughts on reducing file size without loosing accuracy if my end goal is a dxf or dwg?

Sirius

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Re: Reducing Model Size - Maintaining Accuracy
« Reply #1 on: August 25, 2017, 06:00:58 AM »
In workflow generate a mesh.  Do it on high for the maximum number of faces. 
After that is done run decimate mesh from the tools menu.  They key is choosing a suitable number of faces that is the balance between detail in the model and file size.  I guess that depends on what you are modelling and how big it is. 
I would say most Surveying software packages run on regular computers don't really like more than a million faces. and if you can get it down to 250,000 it would be better if you are not loosing too much detail for your purposes.  You will have to try it and see.
Then export it as a .dxf.

Don't try and generate the mesh with a smaller number of faces at the first step.  The result is not the same as generating the mesh on high then decimating to the desired number later.

SAV

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Re: Reducing Model Size - Maintaining Accuracy
« Reply #2 on: August 25, 2017, 06:01:27 AM »
Hi davidsumner,

It will depend on what you are trying to do. For example, for stockpiles I would simply export contour lines which can then be used directly in any CAD software package. They are also generally quite small files, so no issues opening them with traditional CAD software.

If you plan to share a point cloud, you could do some smart filtering/subsampling based on curvature to reduce the file size. For example, you would delete points in flat areas (low/no curvature) and keep more points in complex areas (high curvature). You could do this using CloudCompare (free, open-source). Here is the workflow:
http://www.cloudcompare.org/doc/wiki/index.php?title=Edit%5CSubsample

All the best.

Regards
SAV