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Question

IFC to 3DS loosing quality, "triangles show"

J

Hi!

TLDR: Writing a 3DS from a IFC with scaling of 0.001 and reprojecting from a local coordinate system to SWEREF99 12 00 I loose model quality, scroll to last pic.

 

Info:

I'm trying to convert a IFC model to a format I can use with GIS and Specifically import into ArcGIS PRO / Online. Shape Multipatch writes fine and the quality is there, but file size get big quickly and I loose textures with this writer.

 

Writing from IFC to 3DS without any other transformers yeilds a good result on my model: This quality pretty much looks identical to my INPUT IFC.

If I Scale it 0.001 it also looks acceptable:

if I only reproject I can see some small artifacts, why does this happen and can I fix it?

if I both scale and reproject my output 3Ds is a mess:Why does this happen and any ideas how to fix this?

Thanks in advance

 

JJ

daveatsafe
Safer
Forum|alt.badge.img+19

Hi @jatjat,

The destination format 3DS uses 32 bit floating point coordinates, not the 64 bit floating point used by most GIS systems. Because of this, reprojecting to a coordinate system with high coordinate values will result in a loss of precision when writing to 3DS.

When FME reads the IFC file, it creates a custom local coordinate system from the IFC georeferencing info (if it exists). This coordinate system is also appropriate for 3DS.

However, I would recommend using a Sketchup writer instead of 3DS. This format is also supported by ArcGIS Pro. On the output parameters, set Move to Local Coordinate System to Yes, which will reproject the IFC data to a local coordinate system (if needed), then set the appropriate georeferencing in the Sketchup file.

J
  • jatjat
  • January 29, 2020
daveatsafe wrote:

Hi @jatjat,

The destination format 3DS uses 32 bit floating point coordinates, not the 64 bit floating point used by most GIS systems. Because of this, reprojecting to a coordinate system with high coordinate values will result in a loss of precision when writing to 3DS.

When FME reads the IFC file, it creates a custom local coordinate system from the IFC georeferencing info (if it exists). This coordinate system is also appropriate for 3DS.

However, I would recommend using a Sketchup writer instead of 3DS. This format is also supported by ArcGIS Pro. On the output parameters, set Move to Local Coordinate System to Yes, which will reproject the IFC data to a local coordinate system (if needed), then set the appropriate georeferencing in the Sketchup file.

Thanks for the explanation! It sounds like it should be more skewd when just scaling though? But the weirdness happens only when applying both scaling and reprojecting.

.skp didn't want to import to PRO. So still have the texture issue because I write to SHP multipatch. hm

daveatsafe
Safer
Forum|alt.badge.img+19
jatjat wrote:

Thanks for the explanation! It sounds like it should be more skewd when just scaling though? But the weirdness happens only when applying both scaling and reprojecting.

.skp didn't want to import to PRO. So still have the texture issue because I write to SHP multipatch. hm

Hi @jatjat,

If you have ArcGIS Pro on the same computer as FME, you can write to multipatch geodatabase.

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