[playful music] -[Narrator] Spinosaurus is one of the largest meat-eating dinosaurs ever discovered.

But it’s also the most mysterious.

[snapping] Perhaps the only dinosaur to leave the land behind [water gurgling] and take to the water.

Bringing such a weird dinosaur to life is a major challenge for the Walking With Dinosaurs team.

-[Man] And then what we can do, Steve, you know the shot that we did on the slider yesterday?

-[Steve] Yeah.

-[Narrator] And it starts with filming the environment it inhabited.

Spinosaurus lived in Morocco 100 million years ago.

[vehicle rumbling] -[Stephen Cooter] Morocco today is very much a kind of desert environment but back in the time when Spinosaurus was, was around it was much greener, much more of a sort of enormous river system.

-[Narrator] This unique part of South East Portugal is one of the best matches for the river delta, Spinosaurus called home.

-So we’re here down by this river to film sequence in the film where the Spinosaurus gather to fish.

-[Man] Yeah.

-[Narrator] But today, the weather isn’t being kind.

-[Stephen] Might be time to go back to a van.

Yeah, I think it’s gonna be a bit in and out today but hopefully we’ll get some sun later on.

Hopefully.

-[Narrator] Luckily for the crew, the rain soon clears.

-[Stephen] Good?

-[Narrator] To help imagine the dinosaur action, they use scale cut outs at stand in’s for the digital models.

-[Stephen] It’s a challenge filming things that aren’t there but to try and help us visualize the size and the scale, we’ve got people with poles and we’ve got some tape matches so that we make sure that we actually get the dinosaurs in the frame.

There’s always sort of a lot bigger than you imagine.

-[Narrator] With the stand in’s in place, the team position the camera to capture the action.

-To you Steve, and action.

-[Neil Harvey] I don’t think there’s any way that we would be walking around this close to these creatures but actually for this moment it just feels like the best way to approach it.

You really want to get the camera in there and up close and really feel like you’re, you’re part of it.

-[Narrator] Once the real world environments are captured, it’s time for Spinosaurus to walk in them, which is tough when you’ve been extinct for 94 million years.

[guttural growl] So it’s over to the visual effects team.

-[Kirsty Wilson] We wanted to tell great stories but equally important if not more important, was making sure that we are scientifically accurate and I cannot tell you the level of research that we went to in this series.

-[Narrator] Our hero, Sobec is an entirely computer generated character.

Every detail carefully researched and designed from the claws up.

But unlike the other large predators in Walking With Dinosaurs, Sobec swims.

-[Daniel Miller] Spinosaurus in terms of how it moves, it’s weight distribution, we know what it looks like.

What we need to then sell is how it interacts with the environment.

-[Narrator] And water is particularly tricky to create in the digital world.

[ripping tape] So back in the field.

The team is experimenting with a very unusual piece of equipment.

A perfect scale replica of a Spinosaurus head.

It’s the same color as a blue screen so it can easily be replaced by the visual effects team.

If they can get it to sink.

[driller whirring] After practice in the pool, pushing it through the lake creates the hard to make splashes and ripples in real time.

[baby Spinosaurus squawking] -[Stephen] A physical model would create all the water interaction for us, we can then replace it with our VFX head.

-[Narrator] It gives the animators a huge advantage, letting them blend the Spinosaurus model seamlessly into the real environment.

Enabling this strange dinosaur to walk and swim again.