View creator3d model extends fix (#1980) (#1984)

* initial

* change-log

* handle null union result

* range isNull check

* clean up.

* Remove unnecessary length check.

Co-authored-by: roopksaini <roopksaini@users.noreply.github.com>
Co-authored-by: Paul Connelly <22944042+pmconne@users.noreply.github.com>
(cherry picked from commit 763f8c0)

Co-authored-by: roopksaini <68084841+roopksaini@users.noreply.github.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

common/changes/@bentley/imodeljs-frontend/ViewCreator3d-modelExtends-fix_2021-08-03-17-22.json

@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "packageName": "@bentley/imodeljs-frontend",
+      "comment": "ViewCreator3d fix - modelExtents now computed from all model ranges",
+      "type": "none"
+    }
+  ],
+  "packageName": "@bentley/imodeljs-frontend",
+  "email": "roopksaini@users.noreply.github.com"
+}

core/frontend/src/ViewCreator3d.ts

@@ -91,8 +91,15 @@ export class ViewCreator3d {
     const categories: Id64Array = await this._getAllCategories();
 
     // model extents
+    const modelExtents = new Range3d();
     const modelProps = await this._imodel.models.queryModelRanges(models);
-    const modelExtents = Range3d.fromJSON(modelProps[0]);
+
+    for (const props of modelProps)
+      modelExtents.union(Range3d.fromJSON(props), modelExtents);
+
+    if (modelExtents.isNull)
+      modelExtents.setFrom(this._imodel.projectExtents);
+
     let originX = modelExtents.low.x;
     let originY = modelExtents.low.y;
     const originZ = modelExtents.low.z;