Exclude element without reading his full info

[g-rodigy]

When I try to convert ifc model wich has element IfcGrid without axis names, parse failing even if set excludeTypes: ['IfcGrid'].

Code example

const {convert2xkt} = require('@xeokit/xeokit-convert/dist/convert2xkt.cjs.js')
const WebIFC = require('web-ifc/web-ifc-api-node.js')

const file = 'path/to/model'
const output = 'path/to/output'

convert2xkt({
    WebIFC,
    source: file,
    output,
    excludeTypes: ['IfcGrid', 'IfcGridAxis'],
})

Log output:

INFO:  Parsing Model using IFC2X3 Schema
TypeError: Cannot read properties of null (reading 'map')
    at 3009204131 (...\node_modules\web-ifc\web-ifc-api-node.js:12645:381)
    at IfcAPI2.GetLine (....\node_modules\web-ifc\web-ifc-api-node.js:63239:84)
    at ...\node_modules\@xeokit\xeokit-convert\dist\convert2xkt.cjs.js:15944:51
    at Array.forEach (<anonymous>)
    at parseRelatedItemsOfType (...\node_modules\@xeokit\xeokit-convert\dist\convert2xkt.cjs.js:15942:25)
    at parseSpatialChildren (...\node_modules\@xeokit\xeokit-convert\dist\convert2xkt.cjs.js:15890:5)
    at ...\node_modules\@xeokit\xeokit-convert\dist\convert2xkt.cjs.js:15946:21
    at Array.forEach (<anonymous>)
    at parseRelatedItemsOfType (...\node_modules\@xeokit\xeokit-convert\dist\convert2xkt.cjs.js:15942:25)
    at parseSpatialChildren (...\node_modules\@xeokit\xeokit-convert\dist\convert2xkt.cjs.js:15882:5)

[xeolabs]

Looks like an issue with web-ifc..

[g-rodigy]

Yes, it is web-ifc issue, but i mean can skip element before fully reading his data?

[xeolabs]

If I understand correctly, we have no means to configure conversion to ignore certain IFC elements by ID. This seems to be a useful potential feature though, but outside of our priorities at the moment. If anyone has time for to make a PR, I'd consider merging that though.

[g-rodigy]

Not by ID, by element type as is in the constructor excludeTypes. If I understand correctly code

xeokit-convert/src/parsers/parseIFCIntoXKTModel.js

Lines 279 to 320 in ef646ca

	function parseRelatedItemsOfType(ctx, id, relation, related, type, parentMetaObjectId) {
	const lines = ctx.ifcAPI.GetLineIDsWithType(ctx.modelID, type);
	for (let i = 0; i < lines.size(); i++) {
	const relID = lines.get(i);
	const rel = ctx.ifcAPI.GetLine(ctx.modelID, relID);
	const relatedItems = rel[relation];
	let foundElement = false;
	if (Array.isArray(relatedItems)) {
	const values = relatedItems.map((item) => item.value);
	foundElement = values.includes(id);
	} else {
	foundElement = (relatedItems.value === id);
	}
	if (foundElement) {
	const element = rel[related];
	if (!Array.isArray(element)) {
	const ifcElement = ctx.ifcAPI.GetLine(ctx.modelID, element.value);
	parseSpatialChildren(ctx, ifcElement, parentMetaObjectId);
	} else {
	element.forEach((element2) => {
	const ifcElement = ctx.ifcAPI.GetLine(ctx.modelID, element2.value);
	parseSpatialChildren(ctx, ifcElement, parentMetaObjectId);
	});
	}
	}
	}
	}

Firstrly take some element, then his releated elements and read their data, if element type is excluded then he skiped. The bug happen just in the place where the data is reading (.getLine(...)) for after checking type and other.