# How to convert a PointCloud via tf2

Hey there,

I tried to write some pretty simple code with tf2 and I'm stuck already.

How does one transform a `pcl::PointCloud<...>`

when using `tf2`

(and, less importantly, how about transforming a `sensor_msgs/PointCloud2`

)?
With `tf`

there is the `pcl_ros`

package which can transform pcl-PointClouds with `tf::Transform`

.
There's also pcl's own transformation interface `pcl::transformPointCloud`

which takes Transforms as `Eigen`

matrices.

However, `tf2_ros::Buffer::lookupTransform`

, which seems to be the right interface to use, only returns `geometry_msgs::TransformStamped`

and I can't find a one-liner to convert these (or, well, more likely the wrapped `geometry_msgs::Transform`

to `Eigen::Matrix4f`

or similar.