Plans for a new outdoor industry gathering in Denver, which organizers hope will have a national impact in the future, have progressed to the point where the concept will debut with a “soft opening” this coming spring at Civic Center Park. The Outside Festival, which could help fill the void left when the Outdoor Retailer left Colorado for Utah, will be a joint effort involving Boulder-based Outside Interactive Inc., a prominent outdoor media company that includes Outside magazine, along with the Colorado Outdoor Recreation Industry Office, which is part of the state’s Office of Economic Development and International Trade.