• Advertisement
Sign in to follow this  

Unity Vetting an Idea with Mesh Morphing

This topic is 1645 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

I have a thought on which I would value the community's feedback.


Say you have a tree. For ease of reference, this is just a cylinder. Now, you have an actor swinging an axe. Given a few variables, we know how deeply the axe can "cut" into the tree, the angle of the strikes and so on. Based on these angles and deepness of the cuts, I want to deform the base model potentially separating it entirely, doing some dynamic texture swapping to keep up the illusion you're actually chopping into a tree.


Does anyone see a computational hindrance here even when considering potentially hundreds of NPCs? Would it be possible to "destroy" the original model and have two models if you, say, chopped a wedge out of the side of this tree so they could then be interacted with independently?


No, I have not done any programming work on this myself, yet. I don't want to waste time on something that could prove to be a fool's errand. I'm just asking from a conceptual, theoretical basis. This is the tip of an iceberg should this be doable. I just thought this would be an "easy" starting point. I know there have been some examples with water and pouring between containers and with other liquids. My understanding of them is they work with, more or less, particle systems. This would be with solid models. I've thought about doing this with voxels, and while possible, I would prefer to use traditional models. I would think the tradeoff here would be putting more work on the CPU and GPU if what I'm asking about is doable versus keeping a voxel model and all that contains stored in memory at once.



Share this post

Link to post
Share on other sites

well a model is simply a large list of vertices that you usually store in a GPU vertex buffer and you can refill this buffer at anytime with whatever you want - so yes you can split models or move certain vertices.. in fact animation does this.. and water can also be a large textured plane mesh where you move the vertices..


however, this is pretty complicated stuff that takes a lot of experience to do well and judging by your post im guessing your not that experienced (no offense meant!)..


so - you might want to pin this idea on your wall for a bit later...

Share this post

Link to post
Share on other sites

I've worked on real-time constructive solid geometry before. I suppose you could start with wikipedia:




The system I worked on was purely graphics: the subtraction was done with instances of a cut model being removed from the base model. You could render thousands of cuts on-screen this way, without modifying vertices. There was a 3D texture for the interior.


The part I haven't done is detecting when the model gets split into separate pieces. I assume you want the tree to fall down once that happens. You may be able to use the gpu to voxelize the CSG'd model and do a minimum spanning tree to see if everything's connected, though you probably would have some small limit on how many of those checks you could do per frame. I'm no expert, though. There could be a fast technique I don't know about.


Overall, I think it's possible, but it is complex. Maybe that wikipedia article links to some useful code to get you started. If your game is about chopping stuff, maybe it's worth it. If this is just some background feature in an RPG, I wouldn't bother with it.

Share this post

Link to post
Share on other sites

Thanks for your responses.


EarthBanana, no offense taken. I'm not experienced with game programming, per se, but have been a programmer for about seven years and more an engineer for about three. I understand concepts, though, so I tried to ask with that approach in mind. You've given me something to think about, though, so thanks!


Pink Horror, yes, this would be for an RPG. They're so damned attractive. Even if I fail, the mere pursuit would be worth it, to me. However, instead of trying to be an exact simulationist or traditionalist, I want to bridge the two concepts by making a lot of predetermined choices that the game can use to supplement otherwise inhibitively intense calculations. An example from my reading would be providing material friction coefficients up front rather than trying to calculate that at run time. That's not an intense equation, sure. It is just an example. But, the fundamental approach would be build tiny blocks that work with each other. The result, then, would be a system taking inputs and responding "naturally," insofar as the built-in assumptions are concerned.


I was hoping that by sticking to solid models rather than voxels I could cheat and calculate certain things as I need to rather than trying to keep all the voxels in memory at all times. But, the more I read, the better they seem to be in certain situations.

Share this post

Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
  • Advertisement
  • Popular Tags

  • Advertisement
  • Popular Now

  • Similar Content

    • By bryandalo
      Good day,

      I just wanted to share our casual game that is available for android.

      Description: Fight your way from the ravenous plant monster for survival through flips. The rules are simple, drag and release your phone screen. Improve your skills and show it to your friends with the games quirky ranks. Select an array of characters using the orb you acquire throughout the game.

      Download: https://play.google.com/store/apps/details?id=com.HellmodeGames.FlipEscape&hl=en
    • By Manuel Berger
      Hello fellow devs!
      Once again I started working on an 2D adventure game and right now I'm doing the character-movement/animation. I'm not a big math guy and I was happy about my solution, but soon I realized that it's flawed.
      My player has 5 walking-animations, mirrored for the left side: up, upright, right, downright, down. With the atan2 function I get the angle between player and destination. To get an index from 0 to 4, I divide PI by 5 and see how many times it goes into the player-destination angle.

      In Pseudo-Code:
      angle = atan2(destination.x - player.x, destination.y - player.y) //swapped y and x to get mirrored angle around the y axis
      index = (int) (angle / (PI / 5));
      PlayAnimation(index); //0 = up, 1 = up_right, 2 = right, 3 = down_right, 4 = down

      Besides the fact that when angle is equal to PI it produces an index of 5, this works like a charm. Or at least I thought so at first. When I tested it, I realized that the up and down animation is playing more often than the others, which is pretty logical, since they have double the angle.

      What I'm trying to achieve is something like this, but with equal angles, so that up and down has the same range as all other directions.

      I can't get my head around it. Any suggestions? Is the whole approach doomed?

      Thank you in advance for any input!
    • By khawk
      Watch the latest from Unity.
    • By GytisDev
      without going into any details I am looking for any articles or blogs or advice about city building and RTS games in general. I tried to search for these on my own, but would like to see your input also. I want to make a very simple version of a game like Banished or Kingdoms and Castles,  where I would be able to place like two types of buildings, make farms and cut trees for resources while controlling a single worker. I have some problem understanding how these games works in the back-end: how various data can be stored about the map and objects, how grids works, implementing work system (like a little cube (human) walks to a tree and cuts it) and so on. I am also pretty confident in my programming capabilities for such a game. Sorry if I make any mistakes, English is not my native language.
      Thank you in advance.
    • By Ovicior
      So I'm currently working on a rogue-like top-down game that features melee combat. Getting basic weapon stats like power, weight, and range is not a problem. I am, however, having a problem with coming up with a flexible and dynamic system to allow me to quickly create unique effects for the weapons. I want to essentially create a sort of API that is called when appropriate and gives whatever information is necessary (For example, I could opt to use methods called OnPlayerHit() or IfPlayerBleeding() to implement behavior for each weapon). The issue is, I've never actually made a system as flexible as this.
      My current idea is to make a base abstract weapon class, and then have calls to all the methods when appropriate in there (OnPlayerHit() would be called whenever the player's health is subtracted from, for example). This would involve creating a sub-class for every weapon type and overriding each method to make sure the behavior works appropriately. This does not feel very efficient or clean at all. I was thinking of using interfaces to allow for the implementation of whatever "event" is needed (such as having an interface for OnPlayerAttack(), which would force the creation of a method that is called whenever the player attacks something).
      Here's a couple unique weapon ideas I have:
      Explosion sword: Create explosion in attack direction.
      Cold sword: Chance to freeze enemies when they are hit.
      Electric sword: On attack, electricity chains damage to nearby enemies.
      I'm basically trying to create a sort of API that'll allow me to easily inherit from a base weapon class and add additional behaviors somehow. One thing to know is that I'm on Unity, and swapping the weapon object's weapon component whenever the weapon changes is not at all a good idea. I need some way to contain all this varying data in one Unity component that can contain a Weapon field to hold all this data. Any ideas?
      I'm currently considering having a WeaponController class that can contain a Weapon class, which calls all the methods I use to create unique effects in the weapon (Such as OnPlayerAttack()) when appropriate.
  • Advertisement