Getting canbus traffic from a running vehicle via an ODB port

[Jacobsmess]

Hi, as I understand/have been told. If I'm wanting to read canbus traffic of a vehicle in order to reverse engineer it I'll need software that can make ISOTP requests to get the vehicle ECU to send relevant data.
This is where my understanding ends however.
I'm potentially going to try and get data from a lexus UX300E on its BMS control and 2 can busses. The only way I'm likely going to be able to do this is via an ODB port. So....
Does anyone have any tried and tested methods for doing this?
I've got a Toyota techstream ODB->usb adapter on the way with techstream v18, to access the battery can networks I'll need to make some ISOTP requests, what software (ideally free) exists that can do this and is it easy to then use said software to requests the required data? Thanks

[uhi22]

Need to sort the topics a little bit before going into the details.
There is different kind of communication in the vehicle:
1. The cyclic communication between the control units (e.g. SOC, vehicle speed, temperature, ...)
2. The diagnostic communication, usually triggered by a device which you connect to the OBD port.

Looking on the OBD, usually you will not find the (1). So you are writing "wanting to read canbus traffic" sounds like you want to listen to the cyclic messages, which you normally will never see on the OBD port. Cars have different CAN busses, so you would need to the intended CAN directly.

For using the OBD, there are free (or cheap) apps like CarScanner or TorquePro, which use an bluetooth OBD plug. Personally I used TorquePro a lot, the point is that it needs a specific configuration for each type of vehicle, which defines which data is reached under which service identifiers. In best case, google finds it (search for "TorquePro PIDs Ioniq" for example). In the harder case, if no parameter definition is available, you could use e.g. SavvyCAN to send random diagnostic requests and hope that something senseful comes back.