GPT-4 and ChatGPT. To be more precise gpt-4 with 8k max tokens and gpt-3.5-turbo with 4k and 16k max tokens.

In order to use GPT-4, you need to have granted access to it by OpenAI, read here for more information: https://help.openai.com/en/articles/7102672-how-can-i-access-gpt-4

You can switch between the models in the addon preferences.

More information here: https://platform.openai.com/docs/models

• From 3.3.5 LTS to 3.6 LTS
• Previous versions might work as well, but have not been tested

1. Uninstall the previous version
   1. Open Blender
   2. Go to Edit -> Preferences -> Add-ons
   3. Search for Chat Companion
   4. Click Remove
   5. Restart Blender!
2. Install the new version (follow the steps here in the FAQs)
   1. Go to https://blendermarket.com/account/orders 
   2. Click on "Go to Downloads" for Chat Companion
   3. Download the latest Version
      

Yes, when using the OpenAI API you pay for what you use. Pricing: https://openai.com/pricing

At the moment the prices for ChatGPT are $0.002 / 1000 tokens and GPT-4 costs $0.03 for prompt and $0.06 for completion / 1000 tokens.

For all my testing during development so far I payed $1 in total, so it is very affordable.

Yes! You can get your key here https://platform.openai.com/account/api-keys after you signed up. Once you have your key, just insert it into the addon preferences in Blender and you are good to go.

Step by step:

1. Go to https://platform.openai.com/account/api-keys
2. Click on "create new secret key"
3. 
   
4. Click on "create secret key" in the popup
5. 
   
6. Copy your key
7. 
   
8. Enter it in the addon preferences
9. 
   

To use GPT-4 you need to be accepted after enrolling into the waitlist of OpenAI here: https://openai.com/waitlist/gpt-4-api

As any other Blender Addon. Download the Chat Companion.zip file and leave it as a zip-file, don't unpack it.

1. Open Blender (Restart Blender after uninstalling an older version of Chat Companion)
2. Go to Edit -> Preferences -> Add-ons
3. Click "Install...", navigate to the Chat Companion.zip file and click "Install Add-on"
4. Enable the addon with the checkmark
5. Activate the addon by checking the Checkbox next to it
6. Enter your API Key (get it here: https://platform.openai.com/account/api-keys)

It should then look like this:

You will find the Addon panel in the sidebar of the 3D View (Open/Close with n on your keyboard):