topic Re: Scaling a solid question in Revit API Forum

Scaling a solid question

denisyukJ — Tue, 05 Aug 2025 17:35:55 GMT

Hi,

I have a Solid extracted from wall, now I want to scale 1.1 this solid from the mass center to use updated solid for ElementIntersectsSolidFilter.

Is this code correct cus filter doesn't give me results even when I set factor to 3.0 (much more then I needed)?

double scaleFactor = 1.1; var pivot = solid.ComputeCentroid(); Transform scaleTransform = Transform.Identity; scaleTransform.Origin = pivot; scaleTransform.ScaleBasis(scaleFactor); Solid scaledSolid = SolidUtils.CreateTransformed(solid, scaleTransform);

Re: Scaling a solid question

rcrdzmmrmnn — Tue, 05 Aug 2025 19:47:22 GMT

I think ScaleBasis returns "other" Transform, so you maybe wanna try something like this:

scaleTransform = scaleTransform.ScaleBasis(scaleFactor);

If it doesn't work you could create a DirectShape or even use DirectContext3D to be able to see the created solid and determine what is causing the issue

Re: Scaling a solid question

Mohamed_Arshad — Wed, 06 Aug 2025 07:10:04 GMT

Hi @denisyukJ

As @rcrdzmmrmnn mentioned, the ScaleBasis Method returns the scaled transformation you need to replace the existing transform with. Since you're trying to scale the solid from the origin, Once I object is scaled it moves from the origin, we need to translate it to origin position using Transform.Origin. Refer to the code below for additional reference.

Scale without translate

Transform transform = Transform.Identity; transform.Origin= extractedSolid.ComputeCentroid(); transform = transform.ScaleBasis(2.0); Solid scaledSolid = SolidUtils.CreateTransformed(extractedSolid, transform);

Scale and Translate it to origin

///Instead of Indentity Matrix take the BoundingBox of the Solid Transform transform = extractedSolid.GetBoundingBox().Transform; transform = transform.ScaleBasisAndOrigin(1.1); //After the Translation the Solid will be moved from the origin ///By using translation we can move the Solid to the origin transform.Origin = extractedSolid.ComputeCentroid() - transform.Origin; Solid scaledSolid = SolidUtils.CreateTransformed(extractedSolid, transform);

Visualization Methods

List<GeometryObject> geoObjects = new List<GeometryObject>(); geoObjects.Add(scaledSolid); using (Transaction createSolid = new Transaction(doc, "Visualize Solid")) { createSolid.Start(); DirectShape directShape = DirectShape.CreateElement(doc, new ElementId(BuiltInCategory.OST_GenericModel)); directShape.SetShape(geoObjects); createSolid.Commit(); }

Hope this will helps 🙂

Re: Scaling a solid question

denisyukJ — Wed, 06 Aug 2025 05:08:33 GMT

Thanks both of you @rcrdzmmrmnn, @Mohamed_Arshad for great clarification, especially shape visualization method!

Re: Scaling a solid question

denisyukJ — Wed, 06 Aug 2025 07:16:54 GMT

@Mohamed_Arshad

Wait, strange behavior detected! Pivot point is floating depending of scale factor.

Here is sf=1.1 as I wanted.

Here is sf=2.0 as you mentioned.

Re: Scaling a solid question

Mohamed_Arshad — Wed, 06 Aug 2025 07:15:24 GMT

Hi @denisyukJ

I updated the above code snippet, Kindly check the above reply. Sorry slightly missed in my code. The actual problem was once you scale the object it will move from the location, you need to translate it to original position. Now you can try with any scale factor it will work.

Hope this will helps 🙂

Re: Scaling a solid question

rcrdzmmrmnn — Wed, 06 Aug 2025 12:22:46 GMT

Glad you worked it out 😁