public IHttpActionResult PutModel_3D(int id, Model_3D model_3D)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            if (id != model_3D.id)
            {
                return BadRequest();
            }

            db.Entry(model_3D).State = EntityState.Modified;

            try
            {
                db.SaveChanges();
            }
            catch (DbUpdateConcurrencyException)
            {
                if (!Model_3DExists(id))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }

            return StatusCode(HttpStatusCode.NoContent);
        }
        public IHttpActionResult PostModel_3D(Model_3D model_3D)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            db.Model_3D.Add(model_3D);
            db.SaveChanges();

            return CreatedAtRoute("DefaultApi", new { id = model_3D.id }, model_3D);
        }