In Sales->Quotations the "name" field is working , I need to add my own fields like (x_RDHeight, x_RDLength).

<field name="name"/> is product module variable, automatically working.

<field name="x_RDHeight"/> is customized product module variable, not working giving exceptions like given below

Field(s) `arch` failed against a constraint: Invalid view definition

Error details:

Field `x_RDHeight` does not exist

Error context:

View `sale.order.form`

[view_id: 575, xml_id: sale.view_order_form, model: sale.order, parent_id: n/a]