If something's not working in your scene, test with one of 3D WebView's demo scenes or example projects for comparison.
JavaScript is 3D WebView's "Swiss Army knife". If a C# method doesn't exist for the goal you're trying to accomplish, there's a good chance that you can achieve it with JavaScript browser APIs using IWebView.ExecuteJavaScript(). JS-to-C# message passing may also help.
Tried the tips above and are still encountering issues? Sorry about that! Please contact me.