Interior Designers are cautious of giving away 3D renderings for free because:
1) It takes ~2-4 hours to produce
2) Some Homeowners may hand their designs to another Renovator
3) It can be costly (if they outsource the work)
Common Practices
There’s no standard practice for when you’ll receive 3D drawings however, the 2 common practices are:
Upon Receiving a Deposit
Interior Designers may collect a deposit (~$500 - $2,000). Usually, this amount will be offset from the total quotation.
After in-depth discussion
It might be given at no charge if the IDs are confident that the homeowners are sincere in working with them.