应该设置球的物理特性？

Question

正在使用球的物理特性：

• 高尔夫球

  // Create circle shape
  b2CircleShape circle;
  circle.m_radius = 15.5/PTM_RATIO;
  
  // Create ball shape definition and add to body
  b2FixtureDef ballShapeDef;
  ballShapeDef.shape = &circle;
  ballShapeDef.density = 5000.0f;
  ballShapeDef.friction = 10.0f;
  ballShapeDef.restitution = 0.2f;
  
  ballFixture = ballBody->CreateFixture(&ballShapeDef);
  

• 赛球

  // Create circle shape
  b2CircleShape circle;
  circle.m_radius = 17.0/PTM_RATIO;
  
  // Create ball shape definition and add to body
  b2FixtureDef ballShapeDef;
  ballShapeDef.shape = &circle;
  ballShapeDef.density = 5000.0f;
  ballShapeDef.friction = 10.0f;
  ballShapeDef.restitution = 0.4f;
  
  ballFixture = ballBody->CreateFixture(&ballShapeDef);
  

• ironball

  // Create circle shape
  b2CircleShape circle;
  circle.m_radius = 23.0/PTM_RATIO;
  
  // Create ball shape definition and add to body
  b2FixtureDef ballShapeDef;
  ballShapeDef.shape = &circle;
  ballShapeDef.density = 5000.0f;
  ballShapeDef.friction = 10.0f;
  ballShapeDef.restitution = 0.0f;
  
  ballFixture = ballBody->CreateFixture(&ballShapeDef);
  

• soccerball：

  // Create circle shape
  b2CircleShape circle;
  circle.m_radius = 24.0/PTM_RATIO;
  
  // Create ball shape definition and add to body
  b2FixtureDef ballShapeDef;
  ballShapeDef.shape = &circle;
  ballShapeDef.density = 5000.0f;
  ballShapeDef.friction = 10.0f;
  ballShapeDef.restitution = 0.8f;
  
  ballFixture = ballBody->CreateFixture(&ballShapeDef);
  

• 篮球：

  // Create circle shape
  b2CircleShape circle;
  circle.m_radius = 24.0/PTM_RATIO;
  
  // Create ball shape definition and add to body
  b2FixtureDef ballShapeDef;
  ballShapeDef.shape = &circle;
  ballShapeDef.density = 5000.0f;
  ballShapeDef.friction = 10.0f;
  ballShapeDef.restitution = 0.6f;        
  ballFixture = ballBody->CreateFixture(&ballShapeDef);
  

作为一个新手，我所有的实施都是基于猜测，我遇到了一些麻烦，比如被困的障碍物，该死的障碍物上的慢动作等等，所以如果有更好的解决方案，请把它们放好。 / p>

Answer 1

首先，我建议你不要使用超过100的密度。它会提供不好的模拟。将密度保持在1 - 100的范围内。与动态物体的[0.1,10]范围内的物体大小相同，静态物体的大小最多为50（来自box2d文档）。通常摩擦力设置在0和1之间（也来自box2d文档）。所以你必须在你自己的单位工作，以达到范围。例如，您可以将密度测量为每立方体宽度计的克数。

要评估球的密度，您需要知道它的半径和质量。在这种情况下，您可以找到密度为m / V，其中V是体积。

要测量恢复原状，请在youtube上找一些视频，看看投掷时球的反弹程度。恢复原状是h2 / h1，其中h1初始高度，h2 - 弹跳后的高度

Answer 2

我认为没有任何真正的答案，你可能不得不选择最适合你的方式。虽然有几条评论：密度极高，摩擦力应在0-1之间，高尔夫球恢复原状实际上相当高。我建议从密度1和约0.5的摩擦开始，然后从那里进行调整。