network profile IP range , will VCAC check for existing VM with a ping prior to assigning an IP address?
What are you using for ipam? You have a few options. You can either auto-grab the IP and set it in vCO to update in vCAC (assuming it's either infoblox or has the api ability to do that), grab a chunk of IP's in your ipam solution and mark them as used then add the same ranges in vCAC to use (ipam won't update records this way. It's just a one time). I can tell you upfront that solarwinds ipam does not have the ability to create/udpdate records as "used." We will be switching from it soon because of this.
If you don't use ipam at all and don't know which addresses are used, you could just script it to ping a given set of ip's, and the first that doesn't respond to use that. If it responds go on to the next.
Easiest way to describe this is "internally consistent". It knows about it's own range, but that is all. If you enter a partially consumed range, you will get conflicts.
In honesty, I would suggest one of two things:
1. Grab a range that is only used for vCAC and allocate that to your Network Profile.
2. Fix your internal process for IP Address Management, and use vCO to query whatever system you end up with.
Perhaps it's a two part process