Kentico 12 SP MVC Section view models

I am trying to create sections. I reviewed the documentation here https://docs.kentico.com/k12sp/developing-websites/page-builder-development/developing-page-builder-sections/defining-section-properties and it says “Do not directly pass the property model to your section views. We strongly recommend creating a separate view model class, which you can then use to pass data to the section view." Then immediately go on to provide an example where the property model is passed to the view. So there isn’t an example of passing the view model for the section in the documentation. When I do try to pass the view model I get the error:

The model item passed into the dictionary is of type 'Kentico.PageBuilder.Web.Mvc.ComponentViewModel`1[Katapult.Web.Models.Sections.Column1SectionProperties]', but this dictionary requires a model item of type 'Katapult.Web.Models.Sections.Column1SectionViewModel'.

My Properties

public class Column1SectionProperties: ISectionProperties
{
    [EditingComponent(MediaFilesSelector.IDENTIFIER, Order = 1, Label = "Background Image")]
    [EditingComponentProperty(nameof(MediaFilesSelectorProperties.LibraryName), "Custom")]
    [EditingComponentProperty(nameof(MediaFilesSelectorProperties.AllowedExtensions), ".gif;.png;.jpg;.jpeg")]
    [EditingComponentProperty(nameof(MediaFilesSelectorProperties.MaxFilesLimit), 1)]
    public IList<MediaFilesSelectorItem> BackgroundImage { get; set; }
}

My view model

public class Column1SectionViewModel 
    {        
        public string BackgroundImageUrl { get; set; }
    }

My controller

[assembly: RegisterSection("Column1Section",
                          "1 Column section",
                          typeof(Column1SectionProperties),
                          IconClass = "icon-square")]
namespace Custom.Web.Controllers.Sections
{
    class Column1SectionController : SectionController<Column1SectionProperties>
    {
        public ActionResult Index()
        {
            Column1SectionProperties sp = GetProperties();
            string bgurl = String.Empty;
            var bg = sp.BackgroundImage?.FirstOrDefault();
            if (bg != null)
            {
                Guid g = bg.FileGuid;
                MediaFileInfo mediaFile = MediaFileInfoProvider.GetMediaFileInfo(g, SiteContext.CurrentSiteName);
                if (mediaFile != null)
                {
                    bgurl = MediaLibraryHelper.GetDirectUrl(mediaFile);
                }

var model = new Column1SectionViewModel
              {
               BackgroundImageUrl = bgurl
               }
return PartialView("Sections/_Column1Section", model);
       }

My view

@using Kentico.PageBuilder.Web.Mvc
@using Kentico.Web.Mvc
@using Custom.Web.Models.Sections

@model Column1SectionViewModel

<img src="@Model.BackgroundImageUrl">
@Html.Kentico().WidgetZone()