I'm sure others will chime in on this, but whatever you bring into Camtasia will most likely be some video format you create from AE. I'm not sure what formats are available to use, but I'd guess most likely it will be MOV, since it's a lower third. Because to the best of my knowledge, MOV is about the only format that would support the alpha channel so you could have a transparent background.
Having said that, there will be no way to have any video format "editable" from the aspect of having text you will be able to change. The only real way to have editable text is to have created the Lower Third using Camtasia and Camtasia's elements.
Cheers... Rick :)
Camtasia only supports videos created with the PNG codec exported from After Effects.
Adobe dropped support for that codec after creative cloud 2017. I have both Premier Pro and After Effects cc 2017 still installed on my computer. Strictly in case I want to export something with transparency for use in Camtasia.
In the image below you will see After Effects 2017 with the PNG video codec available. So this is one hoop you’re going to have to jump through, in order to use your lower thirds at all. I’m sure you can download and install 2017 from the creative cloud.
The following image shows After Effects 2018 with the codec no longer available. I haven’t installed the 2019 versions yet. I intend on doing that in the spring after completing current projects. And giving Adobe a chance to work out bugs that might get in my way.
With all the codecs available that support transparency it’s unfortunate that TechSmith only chooses to support one of them. Making it very difficult for people like you and I to do simple things like create lower thirds in a program like after effects.
You cannot edit text created in After Effects in Camtasia. The same way you couldn’t create text in Camtasia and edit it in After Effects. The programs are not created from the same molds, so there incompatible with each other.
If you want to create some really good looking lower thirds with editable text. I suggest you familiarize yourself with Behaviors. Behaviors tends to apply smoother animations than the ones you can apply manually.
If you’re not very careful with manual animations, and get the timing and speed of the animations just right. They tend to jitter and judder a bit. Behaviors seem to have a better handle on the problem. And some of the behavior effects are closer to something you would create in After Effects as opposed to what Camtasia is actually capable of.
If you save that as a project. You can come back and edit the text anytime you wish.
Unfortunately, Camtasia doesn't have the ability to export video with a transparent background. Making it difficult for you to use a lower thirds you create in Camtasia with any other program.
Also, since Camtasia doesn't have blending modes for layers. If your lower thirds lacked the color black altogether. You don't even have the ability to make the background transparent through blending modes.