BIMServerLoaderPlugin not rendering geometries properly

[sha-N]

Hi, I was checking out this SDK as a replacement for BIMSURFER, Great Job 👍.

But Im facing an issue, the plugin loads structural IFC files properly, but for IFC files containing pipes or those type of geometries, the objects look pixelated and shake while moving the camera.

Does this has anything to do with the plugin being based on PerformanceModel.

Is this being worked on?

Originally posted by @sha-N in https://github.com/xeokit/xeokit-sdk/issues/5#issuecomment-464797607

[sha-N]

Side note

BIMSURFER2 which is based on SceneJS renders the above model as follows

and in BIMSURFER3 when quantization is disabled, it also behaves in a similar fashion.

[sha-N]

@xeolabs can you provide some pointers on where to start for resolving this, I just got started on this whole bimserver stuff a week back, trying to catch up on what is available and how is it done.

[xeolabs]

This is a quantization accuracy error, which is not an error within xeokit as such. It is caused by your floating-point geometry losing accuracy when xeokit internally quantizes it to integers. Two things you can try:

• increasing or decreasing the scale of your model
• ensuring that your model is centered at [0,0,0]

For example:

var model = bimServerLoader.load({
    //..
    scale: [0.5, 0.5, 0.5],    
    position: [-90, 0, 0] 
});

[sha-N]

Thank you for the reply, I had tried changing the scale with no luck.

can internal quantization be disabled once, * Download quantized geometry from BIMServer - in progress is done

[xeolabs]

No, quantization can't be disabled. Are you able to share your IFC file, or any IFC file that reproduces this issue for you? Then I can investigate ways to make quantization more robust.

[sha-N]

Yes, I will send you the link in mail, shall i send to this id lindsay.kay@xeolabs.com ?

Please check of a solution as this SDK is kind of a perfect solution for the problem Im trying to solve.

[xeolabs]

Yes, please send to that email, thanks.

[sha-N]

Hi, were you able to reproduce the issue

[sha-N]

Hi, Solved the issue as per your comment by setting the position: parameter.

Right now it is kind of a workaround,

• load the model at position [0, 0, 0]
• get initial camera position
• use inverse of these coordinates on next load as position.

Update

If anybody else face similar issue

Position information can be retrieved from bimserver using ServiceInterface method: "getModelMinBounds" and multiply the coordinates with value of scale

@xeolabs is it possible to avoid the step.

[xeolabs]

@sha-N yes I'll add an option to BIMServerLoader - see https://github.com/xeokit/xeokit-sdk/issues/22