C＃XNA 3D模型无法渲染

Question

The model is a .fbx I have tried many models also, Nothing seems to be working i was wondering if anyone could help me, The following code is all I have thanks!

using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;

namespace _3D
{

    public class Game1 : Microsoft.Xna.Framework.Game
    {
        GraphicsDeviceManager graphics;
        SpriteBatch spriteBatch;
        Model model;
        Matrix[] transforms;

        public Game1()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";
            graphics.PreferredBackBufferHeight = 800;
            graphics.PreferredBackBufferWidth = 1280;
        }

        protected override void Initialize()
        {

            base.Initialize();
        }

        protected override void LoadContent()
        {
            spriteBatch = new SpriteBatch(GraphicsDevice);
            model = Content.Load<Model>("3d/screwdriver");
            transforms = new Matrix[model.Bones.Count];
            model.CopyAbsoluteBoneTransformsTo(transforms);
        }
        protected override void UnloadContent()
        {
        }


        protected override void Update(GameTime gameTime)
        {

            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
                this.Exit();


            base.Update(gameTime);
        }    

        // The draw method is one of the reasons I think nothing is working,

        protected override void Draw(GameTime gameTime)
        {
            GraphicsDevice.Clear(Color.CornflowerBlue);
            Matrix view = Matrix.CreateLookAt(
                new Vector3(200, 300, 900),
                new Vector3(0, 50, 0),
                Vector3.Up);
            Matrix projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45), GraphicsDevice.Viewport.AspectRatio, 0.1f, 10000.0f);
            Matrix baseWorld = Matrix.CreateScale(0.4f) * Matrix.CreateRotationY(MathHelper.ToRadians(180));
            foreach (ModelMesh mesh in model.Meshes)
            {
                Matrix localWorld = transforms[mesh.ParentBone.Index] * baseWorld;
                foreach (ModelMeshPart part in mesh.MeshParts)
                { 
                BasicEffect e = (BasicEffect)part.Effect;
                e.World = localWorld;
                e.View = view;
                e.Projection = projection;
                e.EnableDefaultLighting();

                }
                mesh.Draw();
            }
            base.Draw(gameTime);
        }
    }
}

Answer 1

I don't see anything really wrong with your code, so the problem may be on the model.

It might be caused by the model file in question. There is a know issue with the stock FBX Exporter on Blender (I don't know which modelling software you used to make the model, but the matter is still relevant) that makes the model be exported with a size 100x bigger than it is on Blender. The result is that the model is so big that it not only encloses the camera inside itself, but also is so big that it's polygons are beyond the viewing frustrum. Result: the model is indeed rendered, but it'll never appear onscreen unless you move the camera around until you realise the scaling problem.

I'm saying this because I dealed with this problem myself. If you are indeed using Blender, you should use the exporter found in this page: http://blog.diabolicalgame.co.uk/2011/07/exporting-animated-models-from-blender.html