I have been googling this for the last 30 minutes and for the life of me I can't figure out what I did wrong.  When i use this it creates an explosion somewhere that seems to be related to where I am standing and the block I'm looking at but not actually AT the block.  I'm sure it's a really simple thing I overlooked but I'm just not seeing it.

 

	public void execute(ICommandSender sender, String[] args) throws CommandException {
    	BlockPos blk = sender.getEntityWorld().rayTraceBlocks(sender.getPositionVector(), sender.getCommandSenderEntity().getLookVec()).getBlockPos();
    	sender.getEntityWorld().createExplosion(sender.getCommandSenderEntity(),blk.getX(),blk.getY(),blk.getZ(),5, false);
}

The look vector for an entity is not a position in the world. It's just an angle, basically. You're treating it as a position. (Look vector values are only between -1 and 1).

 

To find the position you are looking at, you can a function found here: http://jabelarminecraft.blogspot.com/p/minecraft-modding-extending-reach-of.html

 

That function only works client side, so a universal version is like so:

 

public static MovingObjectPosition getMouseOverExtendedUniversal(Entity theRenderViewEntity, float dist) {

	AxisAlignedBB theViewBoundingBox = new AxisAlignedBB(
			theRenderViewEntity.posX - 0.5D,
			theRenderViewEntity.posY - 0.0D,
			theRenderViewEntity.posZ - 0.5D,
			theRenderViewEntity.posX + 0.5D,
			theRenderViewEntity.posY + 1.5D,
			theRenderViewEntity.posZ + 0.5D
			);

	MovingObjectPosition returnMOP = null;
	if (theRenderViewEntity.worldObj != null)
	{
		double var2 = dist;
		returnMOP = theRenderViewEntity.rayTrace( var2, 0 );
		double calcdist = var2;
		Vec3 pos = getPositionEyes( theRenderViewEntity, 0 );
		var2 = calcdist;
		if (returnMOP != null)
		{
			calcdist = returnMOP.hitVec.distanceTo( pos );
		}

		Vec3 lookvec = theRenderViewEntity.getLook( 0 );
		Vec3 var8 = pos.addVector( lookvec.xCoord * var2,

				lookvec.yCoord * var2,

				lookvec.zCoord * var2 );
		Entity pointedEntity = null;
		float var9 = 1.0F;
		@SuppressWarnings("unchecked")
		List<Entity> list = theRenderViewEntity.worldObj
				.getEntitiesWithinAABBExcludingEntity(

						theRenderViewEntity,

						theViewBoundingBox.addCoord(

								lookvec.xCoord * var2,

								lookvec.yCoord * var2,

								lookvec.zCoord * var2 ).expand( var9, var9,
								var9 ) );
		double d = calcdist;

		for (Entity entity : list)
		{
			if (entity.canBeCollidedWith())
			{
				float bordersize = entity.getCollisionBorderSize();
				AxisAlignedBB aabb = new AxisAlignedBB(

						entity.posX - entity.width / 2,

						entity.posY,

						entity.posZ - entity.width / 2,

						entity.posX + entity.width / 2,

						entity.posY + entity.height,

						entity.posZ + entity.width / 2 );
				aabb.expand( bordersize, bordersize, bordersize );
				MovingObjectPosition mop0 = aabb.calculateIntercept( pos,
						var8 );

				if (aabb.isVecInside( pos ))
				{
					if (0.0D < d || d == 0.0D)
					{
						pointedEntity = entity;
						d = 0.0D;
					}
				} else if (mop0 != null)
				{
					double d1 = pos.distanceTo( mop0.hitVec );

					if (d1 < d || d == 0.0D)
					{
						pointedEntity = entity;
						d = d1;
					}
				}
			}
		}

		if (pointedEntity != null && (d < calcdist || returnMOP == null))
		{
			returnMOP = new MovingObjectPosition( pointedEntity );
		}

	}
	return returnMOP;
}

 

 

The parameter dist is the max distance to check for a position. The moving object position returned is where you want to spawn the explosion.

 

Dude thank you so much this had me stumped for far too long.