During bidding process, bidders have to submit offers which will suit the customers' requirements. The OPERA project aims at building a decision support tool to help bidders to design offers using CSP and compare them on orignial indicators. The objective is (1) to help bidder to have the same routine for bid answer-ings (2) to help them to design more accurate responses and more efficiently. One of the major tasks during bidding process is offer elaboration, which is in our case, 90% a configuration problem and 10% an innovative design one. Four industrial partners are part of the OPERA project: two in the secondary sector and the two others in tertiary one. This paper presents the first results of this project for open bidding configuration. Therefore, we have built a first version of an open generic bidding model which gathers three types of offers data: (1) context characterization data, (2) data defining the product or service and (3) data defining its delivery process, in case of success. Context data allow to characterize the customer profile, the call for tender characteristics, the bidder profile and the environmental factors. The product is decomposed on subsystems and components using a bill of materials and we propose some tracks to extend our model to services. The process is composed of activities, characterized by a couple (resources, workload). This model has been tested on one use case for each industrial partner. This paper is illustrated by a generic instance of a bike open bidding configuration.