Form Data not serialized in asp.net core mvc controller model

C# model class

public class SubCategoryTwoViewModel
{
    public long Id { get; set; }
    public string SubCatTwoName { get; set; }
    public CategoryViewModel Category { get; set; }
    public SubCategoryOneViewModel SubCatOne { get; set; }
    public string PictureUrl { get; set; }
    public List<IFormFile> File { get; set; }
    public UserViewModel AddedBy { get; set; }
    public DateTime AddedOn { get; set; }
    public UserViewModel Updated_By { get; set; }
    public DateTime? UpdatedOn { get; set; }
    public bool Active { get; set; }
}

Here is the CategoryViewModel

public class CategoryViewModel
    {
        public long CategoryId { get; set; }
}

Here is the controller method

[HttpPost]
public JsonResult AddEditSubCategoryTwo(SubCategoryTwoViewModel model)
{
}

Here is the ajax call which use the Form Data to serialized the data send to the controller method.

var ajaxUrl = ApplicationRootUrl("AddEditSubCategoryTwo", "Category");
var formData = new FormData();
var totalFiles = document.getElementById("subCatFile").files.length;

for (var i = 0; i < totalFiles; i++) {
    var file = document.getElementById("subCatFile").files[i];
    formData.append("File", file);
}

formData.append('SubCatTwoName', self.subCatTwoName());
var category = {
    CategoryId: self.selectCategory()
};

formData.append('Category', category);
var subCatOne= {
    SubCategoryOneId: self.selectCategorytwo()
};

formData.append('SubCatOne', subCatOne);
formData.append('Active', self.active());

$.ajax({
    type: "POST",
    contentType: false,
    processData: false,
    url: ajaxUrl,
    data: formData,
    dataType: "json",
    success: function (data) {
    }
});

I,am getting some field data in the controller but the java script value is not serialized to the controller model.

Here is the screenshot of the sample

In the screen shot I am getting the Category & SubCatOne field as null. But active, SubCatTwoName and File field has receive the value. I want to get Category & SubCatOne value in the controller model object. How can I achieved this.