pass parameters of xacro file in another xacro file

edit

You are not that far from the correct solution you just need some adjustments :

• Your cameras.urdf.xacro should actually use some macros to receive the parameters :

    <?xml version="1.0"?>
    <robot name="camera" xmlns:xacro="http://ros.org/wiki/xacro">
    <xacro:macro name="camera" params="tf_prefix_camera1 tf_prefix_camera2">
        <link name="${tf_prefix_camera1}_pose_frame"/>
        <link name="${tf_prefix_camera2}_link"/>
  
        <joint name="${tf_prefix_camera1)_to_${tf_prefix_camera2)" type="fixed">
          <parent link="${tf_prefix_camera1}_pose_frame"/>
          <child link="${tf_prefix_camera2}_link"/>
          <origin xyz="0.009 0.021 0.027" rpy="0.000 -0.018 0.005"/>
        </joint>
    </xacro:macro>
    </robot>
  

The important parts here are xmlns:xacro="http://ros.org/wiki/xacro" to properly use the macro and to define the macro camera like a function, i.e. specifying its arguments (here its params). Note also that it's not like in the launch files, $(arg ARG) you just need brackets around the name of your param.

• In your other file you just need :

  <?xml version="1.0"?>
  <robot name="camera" xmlns:xacro="http://ros.org/wiki/xacro">
  <xacro:include filename="$(find YOUR_PKG)/urdf/cameras.urdf.xacro"/>
  <camera tf_prefix_camera1="t265" tf_prefix_camera2="d435"/>
  </robot>
  

  In your example you didn't include cameras.urdf.xacro but another urdf file is this a copy/paste mistake ? To call the macro you have previously defined, you just need a tag with the name of your macro and simply assign a value to your parameters. That will simply copy and paste everything from the camera.urdf.xacro file between the <xacro> tag (so everything except the 2 first lines and the last one) and replace the paramaters with their value.