regular angled pipe

ViewController.mm

//
//  ViewController.m
//  RightAngledPipe
//
//  Created by Mizushima Yusuke on 8/16/15.
//  Copyright (c) 2015 Yusuke Mizusima. All rights reserved.
//

#import "ViewController.h"
@import SceneKit;

@interface ViewController ()
@property (nonatomic, weak) SCNView *sceneView;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self setupScene];
    [self createPipe];
    [self createCamera];
}

- (void)setupScene {
    SCNView *sv =  [[SCNView alloc] initWithFrame:self.view.bounds];
    sv.backgroundColor = [self color:0];
    sv.scene = [SCNScene scene];
    sv.autoenablesDefaultLighting = YES;
    sv.allowsCameraControl = YES;
    [self.view addSubview:sv];
    
    self.sceneView = sv;
    
}

- (void)createPipe {
    SCNNode *p = [[self pipeNode] flattenedClone];
    p.position = SCNVector3Make(0, 6, 0);
    [self.sceneView.scene.rootNode addChildNode:p];
    
    SCNNode *pb = [p flattenedClone];
    pb.position = SCNVector3Make(2.8, 3, 0);
    [self.sceneView.scene.rootNode addChildNode:pb];
    
    
    SCNNode *pc = [p clone];
    pc.position = SCNVector3Make(5, 0, 0);
    pc.rotation = SCNVector4Make(0, 1, 0, -M_PI * 0.5);
    [self.sceneView.scene.rootNode addChildNode:pc];
    
    
    SCNNode *pd = [p clone];
    pd.position = SCNVector3Make(5, -3, 2.5);
    pd.rotation = SCNVector4Make(0, 1, 0, M_PI);
    [self.sceneView.scene.rootNode addChildNode:pd];
}

- (SCNNode *)pipeNode {
    SCNNode *pipeNode = [SCNNode node];
    
    for (int i=0; i<10; i++) {
        SCNNode *ringV = [self ring];
        ringV.position = SCNVector3Make(0, 1.28 - i * 0.1, 0);
        [pipeNode addChildNode:ringV];
        
        SCNNode *ringH = [self ring];
        ringH.rotation = SCNVector4Make(0, 0, 1, M_PI * 0.5);
        ringH.position = SCNVector3Make(0.375 + i * 0.1, 0, 0);
        [pipeNode addChildNode:ringH];
    }
    
    int cnt = 20;
    float dw = M_PI * 0.5 / cnt;
    for (int i=0; i<=cnt; i++) {
        float w = i * dw + M_PI;
        float x = 0.3 * cos(w) + 0.3;
        float y = 0.3 * sin(w) + 0.3;
        SCNNode *r = [self ring];
        r.rotation = SCNVector4Make(0, 0, 1, w);
        r.position = SCNVector3Make(x, y, 0);
        [pipeNode addChildNode:r];
    }
    
    pipeNode.physicsBody = [SCNPhysicsBody staticBody];
    pipeNode.physicsBody.physicsShape = [SCNPhysicsShape shapeWithNode:pipeNode options:@{SCNPhysicsShapeTypeKey : SCNPhysicsShapeTypeConcavePolyhedron}];
    pipeNode.physicsBody.friction = 0;
    pipeNode.physicsBody.restitution = 0;
    return pipeNode;
}

- (SCNNode *)ring {
    int cnt = 40;
    float r = 0.3;
    float dw = 2.0 * M_PI / cnt;
    SCNNode *ring = [SCNNode node];
    for (int i=0; i<cnt; i++) {
        float x = r * cos(dw * i);
        float z = r * sin(dw * i);
        SCNBox *box = [SCNBox boxWithWidth:0.1 height:0.1 length:0.05 chamferRadius:0];
        box.firstMaterial.diffuse.contents = [self color:4];
        SCNNode *boxNode = [SCNNode nodeWithGeometry:box];
        boxNode.position = SCNVector3Make(x, 0, z);
        boxNode.rotation = SCNVector4Make(0, 1, 0, -dw * i + M_PI * 0.5);
        [ring addChildNode:boxNode];
    }
    
    return ring;
}

- (void)createCamera {
    SCNNode *camera = [SCNNode node];
    camera.camera = [SCNCamera camera];
    camera.position = SCNVector3Make(0, 0, 20);
    [self.sceneView.scene.rootNode addChildNode:camera];
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    SCNSphere *ball = [SCNSphere sphereWithRadius:0.25];
    ball.firstMaterial.diffuse.contents = [self color:2];
    SCNNode *ballNode = [SCNNode nodeWithGeometry:ball];
    ballNode.position = SCNVector3Make(0, 10, 0);
    ballNode.physicsBody = [SCNPhysicsBody dynamicBody];
    ballNode.physicsBody.friction = 0;
    ballNode.physicsBody.restitution = 0;
    [self.sceneView.scene.rootNode addChildNode:ballNode];
}

#define ColorHex(rgb) [UIColor colorWithRed:((rgb & 0xFF0000) >> 16)/255.0 green:((rgb & 0xFF00) >> 8)/255.0 blue:(rgb & 0xFF)/255.0 alpha:1.0]
- (UIColor *)color:(int)i {
    if (i > 4) return nil;
    int code[] = {0xF6F792, 0x333745, 0x77C4D3, 0xDAEDE2, 0xEA2E49};
    return ColorHex(code[i]);
}

@end