Achieving trapdoor style movement in GZDoom

[Knas]

I've been looking for ways to make trapdoor/drawbridge style movement for, well, trapdoors and drawbridges, but also for books and containers. From what I've read you can't do this with polyobjects or 3d floors, but is it possible in some other way like 3d models or something else?

Unrelated; Can you make a double sided polyobject show its floor and ceiling?

[Jaxxoon R]

Basically, either question can be answered as "with 3D models."

To go into detail, you can animate a rectangular 3D model in any way you wish, but you can't rotate or change the object's actual hitbox. So to do something like a drawbridge you'd have to make the (no-solid) actor do it's thing and then have an invisible 3D floor serve as its collision once its in place. And then make sure the player and monsters can't reach or otherwise interact with the drawbridge all the while it is animating.

Non-infinitely tall polyobjects are a thing we're kind of lucky to have in Zdoom, honestly, and the only version of the Doom engine I know of that draws tops/bottoms for its Polyobj platforms is SRB2.

However, I saw not too long back a way of creating 3D platforms using models and a good helping of scripting. I'm not too familiar with the inner workings, however so I can't comment on it. I'm wanting to say it might've been made by Kappes Buur, though I don't remember.

[Gez]

Polyobjects are just line, so they do not have flats.

(Sonic Robo Blast 2, which is a Sonic fangame built on a very advanced and customized version of Doom Legacy, does have polyobjects with top and bottom textures; but everything not related to playing SRB2 was removed.)

You can make the polyobject invisible, and have a model with the same shape follow the same movement. That allows a wide variety of movement, however be aware that it will still not be possible to dynamically change the slope of any plane. You can, again, cheat by using a 3D model, however the collision/physics part will not work, so make sure that the movement is too fast for the player to notice a collision glitch or the movement happens while the player cannot walk on the trapdoor/drawbridge.

[Knas]

Those ideas work just fine. The player will never directly interact while it's moving. It's just the animation that's important. Now it's time to learn how to make 3d objects I guess. :p

[Kappes Buur]

Similar to the moving floor effect with the bridge ( https://www.doomworld.com/vb/post/1526789 )
I applied this effect to a trapdoor. Who knows, it might work for you.

[Voros]

Knas said:

Those ideas work just fine. The player will never directly interact while it's moving. It's just the animation that's important. Now it's time to learn how to make 3d objects I guess. :p

Try Blender.

Also, maybe instead of a real trap door, why not a very fast elevator? When the player walks on it, it immediately triggers the event and will happen once only. Not exactly sure if such a flag exists, but I'm sure it does.

[Knas]

Similar to the moving floor effect with the bridge ( https://www.doomworld.com/vb/post/1526789 )
I applied this effect to a trapdoor. Who knows, it might work for you.

Try Blender.

Also, maybe instead of a real trap door, why not a very fast elevator? When the player walks on it, it immediately triggers the event and will happen once only. Not exactly sure if such a flag exists, but I'm sure it does.

Like I said, it's not the necessarily the functionality that is important here. Just the visual of a floor opening. But thanks for the tips.

[Voros]

Knas said:

Like I said, it's not the necessarily the functionality that is important here. Just the visual of a floor opening. But thanks for the tips.

So you want to create an animation? That's it? So you don't want to implent it into a Doom map right?

In that case, ever heard of Risen3D? Its a sourceport that allows 3D models to be implented (I know EDGE can do this too). With some working around of the map and model, ypu could create such an event.

Animations can be made in most 3D modellers, like Blender, 3DS Max, etc. You just need some tips on what to do first.