The well-known engineering firms that are involved in the Neom project and have expressed their opinions include:
1. Morphosis: This architectural firm is involved in the design of part of "The Line" within the Neom project.
2. OMA (Office for Metropolitan Architecture): This firm is also participating in the design of part of the Neom project.
3. Adjaye Associates: This architectural firm is engaged in the design of part of the Neom project.
4. Peri Cobb Freed & Partners: This firm is also involved in designing part of the Neom project.
5. Studio Fuksas: This firm is engaged in the design of part of the Neom project.
6. Tom Wiscombe Architecture: This architectural firm is participating in the design of part of the Neom project.
7. UNStudio: This firm is also involved in the design of part of the Neom project.
8. Coop Himmelb(l)au: This firm is participating in the design of part of the Neom project.
9. HOK: This firm is engaged in the design of part of the Neom project.
10. Oyler Wu Collaborative: This firm is also involved in the design of part of the Neom project.
11. Delugan Meissl Associated Architects: This firm is engaged in the design of part of the Neom project.