php - L5 Form Model Binding with multiple Parameter -

how make form::model multiple parameter? have example route this. www.domain.com/product/2/product-attributes/3/edit in normal form can this:

<form method="post" action="{{ route('product.{product}.product-attributes.update', [$product->id, $product-attribute->id ]) }}"> </form> 

but if im trying use laravelcolective/html form::model() this:

form::model($productattributes, array('method' => 'post', array('route' => array('product.{product}.product-attributes.update', [$product->id, $product-attribute->id ]))) 

i error array string conversion...

==== update ==============

my routes:

route::resource('backend/product', 'backend\productcontroller'); route::resource('backend/product/{product}/product-attributes', 'backend\productattributescontroller',['except' => ['index']]); 

===== update 2 =========================

already solved prove route not wrong php artisan route:list

im trying.. if normal route use array pass multiple parameter. guess form::model dont need use array separate ,

normal route ::

<form method="post" action="{{ route('product.{product}.product-attributes.update', [$product->id, $product-attribute->id ]) }}"> </form> 

form model ::

form::model($productattributes, array('method' => 'post', array('route' => array('product.{product}.product-attributes.update', $product->id, $product-attribute->id)))