Best way to get properties of all physical elements

[lijiayi0921]

Hi,

I'm trying to get a selection (by name for example) of attribute properties of all PhysicalElements present in a model.

For properties, I currently do so with presentation.getConent :

    // having acquired classFullName and id of all physical elements inside "props" :

    const options = {
        imodel, rulesetOrId: DEFAULT_PROPERTY_GRID_RULESET, keys: new KeySet(props.map(prop => {
            return {
                classFullName: prop.classFullName,
                id: prop.id,
            };
        }))
    };
    const descriptor = await Presentation.presentation.getContentDescriptor({ ...options, displayType: "Grid" });
    if (descriptor) {
        return await Presentation.presentation.getContent({ ...options, descriptor });
    }

This solution works. However the response json may be very large and takes a lot of time to download.

What would be the right way to get attribute properties names / values ?

Thanks
Jiayi

[grigasp]

You can specify what properties you want using the fieldsSelector attribute when requesting content.

When requesting content for many elements I'd also recommend doing that in pages. We found that the most efficient way to do it is by paging the KeySet you're passing to getContent. We have a function on the backend that you could use as an example - PresentationManager.getElementProperties.

I would also like to raise a question why you need to download properties of all PhysicalElement elements to the frontend. For large iModels that can be millions of elements and will never be efficient.

[lijiayi0921]

Thanks @ColinKerr for the answer. I'll let you know when I have more questions :)

[grigasp]

@grigasp I created this sandbox which should demonstrate the issue, but it has some errors... https://www.itwinjs.org/sandboxes/Jiayi/Jillayne-the-aqua-owl-882

@lijiayi0921, please have a look at this: https://www.itwinjs.org/sandboxes/grigas/Opaline-the-gray-kite-479

[lijiayi0921]

Thanks a alot @grigasp !
I rewrote elemProps with ecsql in order to improve the performance.
Code creating an array of element items is added to log all items with properties.

In the model "CoffsHarborDemo", I look for 2 fields : 'Sloped Area', 'Name'
The result array does not contain those properties except for the first item

[grigasp]

Let's break that down by property:

• Sloped Area property exists only on the orddgn.VolumetricQuantityAspect class. I see there are some of its instances, but none of them have a relationship to a bis.PhysicalElement instance. This is the reason you're not even getting this property in the content descriptor.

• Name property comes from the relationship path bis.Element -> bis.ModelContainsElements -> bis.Model -> bis.ModelModelsElement -> bis.PhysicalPartition -> bis.ElementHasLinks -> bis.RepositoryLink.UserLabel. An content item is only going to have this property fs the target instance exists on this relationship path. I ran this query:

  select count(1)
  from bis.physicalelement pe
  join bis.physicalpartition pp on pp.ecinstanceid = pe.model.id
  join bis.ElementHasLinks ehl on ehl.sourceecinstanceid = pp.ecinstanceid
  join bis.repositorylink rl on rl.ecinstanceid = ehl.targetecinstanceid

  It tells me there are 3 physical elements whose model has a related repository link. I looked at the stuff you log into console and confirmed there are 3 records that have this property. Indexes in the array: 0, 677, 678.

So as far as I can tell everything works as expected.

[lijiayi0921]

@grigasp Thanks now I understand better how it works.
I wrote a comment with examples of fields causing returned contentSet to be empty. But github keeps saying "You can't comment at this time."
It happends when I test with an ifc file
How can I send you the example ?
Thanks