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Orbicles
About Truespace Archives
These pages are a copy of the official truespace forums prior to their removal somewhere around 2011.
They are retained here for archive purposes only.
Orbicles // Work in Progress
Post by W!ZARD // Oct 30, 2007, 1:18am
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W!ZARD
Total Posts: 2603
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I'm afraid that layers and booleans are not very compatible... and probably should not play in the same sandbox.
Hmmn. (He hummed a thoughtful hum). I'm not sure why you would say this - although subtracting item 1 on one layer from item 2 on a second layer while having a third layer selected will lead to a result that's all on the third layer which can be confusing if your not expecting it - otherwise I find layers and booleans work fine together. Again it's a question of forward planning.
I often copy the object(s) I'm appling the boolean transform to all to a new layer, save the scene, then do the boolean with only the relevant layers active.
Each small sphere has a doorway (already cut with a cylinder). Each needs to have a bite out of either side (made by adjacent lower spheres). I think I need to:
1.Join (boolean) two large spheres (they just touch each other) - and save as one object (if I can).
2.Start a fresh project with one small sphere.
3.Load the conjoined-twin spheres and try to boolean subtract them from the small sphere.
4.Save.
5.Clean up the geometry.
6.Save
That should work I think - hard to say for sure without knowing the geometry involved. Re your first point, boolean Object Union is usually the least troublesome of the boolean tools and the Undo tool (or CNTRL+Z) usually works fine if required.
Here's how I would do it (FWIW;))
First Add New Layer
Copy your two spheres to this layer and Object Union them
Copy or otherwise create the 'key' shape you wish to be subtracted and position appropriately.
Save your scene
'Object Subtract' the key shape from the target shape - note that if you get unexpected results the Undo feature will almost always return you to the pre-boolean state.
With regard to tidying up the resulting geometry you can often get useful results by simply applying a layer of Subdivision to your object - trueSpace will do a certain amount of tidying up before applying the SDS which remains when you then remove the layer of SDS again.
Finally assuming you are happy with the result you can reactivate the earlier layer(s) with your original objects in them and delete them.
Using layers like this adds an extra level of backup and there's nothing wrong with multiple redundancy IMO.
You've suggested saving your objects and doing the booleans in a new scene - I'd just do he same thing in the original scene using the layers. In my opinion the layers feature - or something very much like it - should be the very next thing transferred from the model side to the Workspace.
Anyway, I hope that helps - let us know how you get on. |
Post by butterpaw // Oct 30, 2007, 7:16am
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butterpaw
Total Posts: 831
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Hmmm (my turn) much food for thought there.
About the layers.. I really do find them useful, but didn't understand why items were moving from layer to layer ... thanks for the explanation! I will continue to use the layers :)
I did a lot of experimentation with the boolean operations, saving the results of each separately (I should show those, and will try to find time to get them uploaded), and in fact, I should probably make another post specifically for that.. there are a number of settings for subtraction, and the order in which SDS is applied seems to make a difference. |
Post by butterpaw // Nov 1, 2007, 3:09am
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butterpaw
Total Posts: 831
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I probably should have illustrated what I said in my previous post.
However, I decided to move on with this instead:
9347
I wondered why this central piece kept being left behind by boolean subtraction, until I finally realized that using a 'shelled' sphere meant that the only 'solid' part of the sphere was the shell and that would be the only part that would be subtracted! :p
I probably should have made another simple sphere of same size to do a cleaner subtraction, but it's already done, so I think I don't need to do it again.
Here both sides are removed:
9348
I have to remove more faces by hand to get this shape:
9349
However, now I see some problems:
9350
So now, I need to know what the best course to follow here:
9351
I'm thinking that the parts that will butt up against other objects do not need to be (and should not be) closed with faces, but the few areas which may be exposed to view should be closed....
I'd really appreciate feedback/advice on this! :) |
Post by opiejuan // Nov 1, 2007, 4:06am
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opiejuan
Total Posts: 120
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I wondered why this central piece kept being left behind by boolean subtraction, until I finally realized that using a 'shelled' sphere meant that the only 'solid' part of the sphere was the shell and that would be the only part that would be subtracted! :p
You are right on
]I'm thinking that the parts that will butt up against other objects do not need to be (and should not be) closed with faces, but the few areas which may be exposed to view should be closed....
I'd really appreciate feedback/advice on this! :)
Personally, if those faces or edges or the lack thereof do not affect the rendering or final output I wouldn't worry about them. If you think there might be a time later on when they might cause a problem, then it's better to solve it now than later....but this is just my opinion
You have come a long way in last little bit, keep going! It just keeps getting easier and easier as you go. |
Post by butterpaw // Nov 1, 2007, 4:24am
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butterpaw
Total Posts: 831
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Thanks OpieJuan! (fun name :D)
The items I am modeling are for a game, and will need to be rendered in realtime, so poly count is an issue...
Further notes on previous observations I've made:
If I boolean union the two large spheres before subtracting them from the the smaller one.. the large spheres become deformed by the process (which is a result I don't want). Therefore I subtracted them separately.. This seems to have worked. |
Post by Jack Edwards // Nov 1, 2007, 5:18am
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Jack Edwards
Total Posts: 4062
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I would clean up the geometry as you go along. Especially those N-gon surfaces which won't export your game engine. It's really easy to miss them later when the model gets more complex.
As for deleting hidden surfaces, I'd generally recommend saving that for the final step when you optimize your model prior to exporting, since it may cause issues with the model side tools which like closed objects. For workspace side it's less of an issue. Of course, if it's a complex model and that part will be hard to get to or remember later, then like with fixing the geometry it might be good to do it as you go along. |
Post by 3dfrog // Nov 1, 2007, 5:21am
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3dfrog
Total Posts: 1225
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In some game engines open objects cause shadow artifacts. So you want to close those edges. Especially if you are using 3dgamestudio. |
Post by butterpaw // Nov 1, 2007, 9:07am
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butterpaw
Total Posts: 831
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Hmmm, ok yes I am going to be using 3DGS (3D Game Studio) ...
However, since the other spheres are going to be put back in the locations they were in when using them to do the subtractions (as per my previous image, shown again below) I thought I would weld verts from the small spheres onto the larger ones.' The idea was to allow the three lower larger spheres not to have 'bites' taken out of them by the smaller spheres.. but the smaller spheres take 'bites out of the top sphere... still leaving the top sphere, with a floor placed at equator, enconmpassing quite a large space.
http://forums1.caligari.com/truespace/attachment.php?attachmentid=9174&d=1193319750
This image isn't quite correct, becuase the lower large spheres actually intersect the smaller ones just below the equators of the smaller spheres.. allow them to have their floors at the larges diameter.
So, there will be three of these smaller partial sphere objects glommed onto the three lower large spheres.
Does that make sense? |
Post by rjeff // Nov 1, 2007, 10:22am
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rjeff
Total Posts: 1260
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Jack what do you mean by N-gon. I see this term alot. |
Post by Jack Edwards // Nov 1, 2007, 10:22am
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Jack Edwards
Total Posts: 4062
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If you're welding it, you'll need to make sure to delete the interior polygons before welding. |
Post by Jack Edwards // Nov 1, 2007, 10:23am
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Jack Edwards
Total Posts: 4062
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N-gon's are polygons with more than 4 sides. |
Post by frootee // Nov 1, 2007, 12:16pm
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frootee
Total Posts: 2667
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Wow looks like you are making some serious progress here Butterpaw. Keep it up! You can learn a lot by projects like this! I am looking forward to seeing the finished product. |
Post by butterpaw // Nov 1, 2007, 12:32pm
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butterpaw
Total Posts: 831
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Here's the thing.. the object I showed above has places (where it's been cut by subtraction) where there are faces in some spots and not faces in others.. i.e. inconsistent.
I felt (still feel) unable to make the decision (in view of all the various considerations placed before me. Do I close them all? or open them all?
I have used 3d canvas in the past, and the old-school train and plane modelers there (who do some beautiful modeling, by the way) are quite adamant about removing faces which will be flat against other faces.. i.e. if you are laying a path (or railbed) down on the ground mesh, or putting one building tight up against another .. the 'hidden' faces must be removed... as the engine would have to render them even if you can't see them (they mostly use Blitz 3D). And they are totally focused on keeping poly counts low (with good reason in most cases)
However, I do know that 3DGS functions differently .. for example, you don't need 'airlocks' or gaterooms with doors placed between indoor and outdoor scenes, the engine determines what will be visible to the player and renders only that. In this case it may be ok to leave the faces on, and in fact make sure the 'shell' which is almost two separate objects, becomes one cosed object (the inside being the space between the shells)
I do understand that you can place objects right next to each other without welding them together, and they won't come adrift, and that sometimes this is advantageous.
However, I'm thinking, with a building as complex as this one, I would imagine it to be easier to make it one (rather complex) object. To ensure that all parts are imported to exactly the right locations with respect to each other. (is that an unnecessary worry?)
@Jack .. re n-gons. In one of my illustrations above.. I see where on the outside of the shell there are two quadrilaterals, on the inside of the shell there appears to be an n-gon. This seemed so strange, as if maybe trueSpace was just not showing what is actually there. should I assume "if it looks like an n-gon - it must be an n-gon"? and add the necessary edges?
Well maybe this is confusing without good illustrations.. and I should approach it again later ^_^
thanks very much for interest and help!'
@ frootee - thanks for cheering me on - I really appreciate the positive push ^_^ |
Post by frootee // Nov 1, 2007, 12:41pm
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frootee
Total Posts: 2667
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I am not sure how nurbs play into games applications but, instead of using booleans, have you considered nurbs spheres, and using projections to remove the parts you don't need? You can use a closed curve (part of a sphere, for example), to project a curve onto your sphere surface, and remove that portion of the nurbs curve. Then, you can convert the nurbs sphere to a polygon shape.
You can also connect spheres like this together using the surface blend tool.
I don't know how converting the nurbs sphere to to a polysphere affects geometry; whether you get all triangles or a blend of triangles, quads, and n-gons.
But it may be worth considering.
Any thoughts?
Froo |
Post by butterpaw // Nov 1, 2007, 2:13pm
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butterpaw
Total Posts: 831
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I'm not sure either, but it would be interesting to know. I'm pretty sure I don't want to change from my present path on this particular model, but there are going to be other ones, where this might really be the preferred method, if it can be used... |
Post by Jack Edwards // Nov 2, 2007, 3:10am
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Jack Edwards
Total Posts: 4062
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I think nurbs would be more pain than it would be worth. Since you'd have to convert to poly anyway before exporting. You could use a nurbs object or set of splines as guides for your polygon modeling, though.
About the n-gons. If you're not sure if there are extra verts, you can grab each of the verts in sequence and move them around to make sure everything is connected up right and to see if there are any hidden verts hanging around. If you're worried about loosing and exact positioning of a vert, you can use a workflow of move then undo, select the next, move then undo, etc. |
Post by butterpaw // Nov 2, 2007, 3:15am
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butterpaw
Total Posts: 831
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Right - thanks!
Careful and methodical. This is why I was asking about the 'points view' .. I'll need to move it to Workspace and have a good look :) |
Post by butterpaw // Nov 6, 2007, 10:21am
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butterpaw
Total Posts: 831
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@WIZARD -
"Orbicles" cool word!
First make a sphere then copy it.
Next resize the new sphere and paint it with a different colour - any colour will do at this stage. This will allow you to easily apply a different material to the inside.
Next, select the large sphere and using the Boolean subtract tool click the smaller sphere to simultaneously hollow out your large sphere and paint a different material to the inside. You can then subtract an entry hole to access the inside of your hollow sphere
I have two questions on this.. I've been trying it for a while, with inconsistent results....
How do you select the inside sphere in order to subtract it from the outside sphere? maybe I'm just being dense but trueSpace does not appear to automatically select the next layer or item... I've accomplished it once or twice, but don't quite know how I did, and can't reproduce it consistently.
lol.. did I forget the second question?
uhm.. oh yeah.. what is that advantage of doing it this way instead of using boolean shell tool?
I realize you may have told me and it slid by me... in which case.. please remind me? :)
:confused:
BTW, I haven't stopped working on this at all.. it's just that I've restarted several times :p by now I have the settings pretty well worked out (and somewhat improved) and am ready to start subtractions (or shell) again.
Thanks! :) |
Post by opiejuan // Nov 6, 2007, 10:36am
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opiejuan
Total Posts: 120
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@WIZARD -
I have two questions on this.. I've been trying it for a while, with inconsistent results....
How do you select the inside sphere in order to subtract it from the outside sphere? maybe I'm just being dense but trueSpace does not appear to automatcally select the next layer or item... I've accomplished it once or twice, but don't quite know how I did, and can't reproduce it consistently.
:confused:
BTW, I haven't stopped working on this at all.. it's just that I've restarted several times :p by now I have the settings pretty well worked out (and somewhat improved) and am ready to start subtractions (or shell) again.
Thanks! :)
Try a couple of things to see if it will help you some. First, do as Wizard suggests by applying different textures to the 2 spheres. When you are ready to do the boolean subtraction, switch to a wireframe view. In solid display you cannot see the inner sphere and so don't get the immediate visual feedback from the boolean operation.
As long as there are no other objects near where you are going to click on the inner sphere, tS will do a pretty good job of selecting the correct object to work with. Working in wireframe will help you see if anything else will get in the way.
HTH |
Post by butterpaw // Nov 6, 2007, 11:05am
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butterpaw
Total Posts: 831
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Thanks, Opiejuan!
That sounds like a good idea. I noticed that what kept happening is that it would subtract the large sphere from itself. and .. disappear. and no.. it didn't go to another layer (unless it's an invisible alternative universe layer) .. I simply wound up with zero objects (and btw I had already colored them differently).
When it works, I can also tell because some 'other colored' triangles tend to show in the surface as the light hits the outer and inner layers as I move around the object (I've been working with objects in translucent surface-wireframe display)
However if it will let me click 'through' the larger sphere and hit the wireframe of the inner sphere, that might just do it. Too bad - it's hours before I'm going to be able to try this out.. :D |
Post by opiejuan // Nov 6, 2007, 12:12pm
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opiejuan
Total Posts: 120
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One more thing. If you already know this then just disregard...but when doing boolean operations you always want to work in a certain order. You want to start with the main object, or the object you want the operation to be performed ON. In your case it would be the larger sphere because it is the object you want to remain after the operation takes place.
Next you would click on the boolean tool of choice
Then finally click on the object that will be used as the shape that will affect the main object...in your case the inner or smaller sphere.
Doing it in reverse order, i.e. selecting the smaller sphere, click the boolean subtract tool, then clicking the larger sphere would make you end up with nothing at all since ALL of the larger sphere subtracted from the smaller sphere would effectively wipe out the entire smaller sphere.
Man, I hope I explain these well enough to make sense. Let me know if not and I'll try again :) |
Post by butterpaw // Nov 6, 2007, 12:50pm
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butterpaw
Total Posts: 831
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Makes perfect sense OpieJuan, and indeed I do already now about the order of operations. What I was explaining was that I was unable to click on the smaller (inner) sphere as the 2nd item, because being inside of the other .. it requires an extra click to select it if it were half across it or so, I could easily click it with the (-) subtraction. So, instead, what happens is that when I try to click the inner sphere I wind up clicking the original (target) sphere and it deletes itself - i.e. subtracts itself from itself, leaving zero (evidently). I could be misinterpreting what I see, of course.
Well I will try things out when I get home... and thanks again ^_^ |
Post by frootee // Nov 6, 2007, 12:57pm
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frootee
Total Posts: 2667
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I think using the shell tool is the way around that butterpaw. You can set the shell depth (or is it thickness?) to get the desired effect. It's with the other boolean tools I think. |
Post by butterpaw // Nov 6, 2007, 1:07pm
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butterpaw
Total Posts: 831
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Mmm yeah, that was my other question, whether there is some definite advantage to doing the subtraction operation, instead of the shell operation. Especially as you can set the depth...
My first choice was to use the shell operation, but the subtraction operation was suggested as an alternative
My only guess on that, is that perhaps the subtraction operation would ensure that you can easily have a different texture/material on the inside than on the outside? .... but I'm really not clear on this ... :p
To anyone reading/answering this thread I am using tS7.51 and performing all operations on model side (at this point, anyway). |
Post by frootee // Nov 6, 2007, 1:12pm
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frootee
Total Posts: 2667
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Ah I see.
I seem to remember that an object could use two colors / textures (without the need for a boolean); one for the inside, one for the outside. Been a long time since I messed with that though. So, I could be wrong.
I wonder if you can specify that in a setting with the shell tool: inside color / outside color (or texture).
Maybe I'm thinking of OpenGL primitives... |
Post by butterpaw // Nov 6, 2007, 1:22pm
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butterpaw
Total Posts: 831
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Well, possibly W!ZARD will happen by with an explanation (since he suggested this method). :)
Meanwhile,(and at any time) anyone can suggest anything - I am learning from all the different things I try out - the discussions are often as valuable as the actual process of modeling. :D |
Post by opiejuan // Nov 6, 2007, 1:24pm
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opiejuan
Total Posts: 120
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I don't really have any experience with the shell tool either on this matter. I do know that the boolean subtract when just dealing with 2 spheres in this case is pretty bulletproof.
another note: The texture on the smaller sphere will be placed in the inside cavity left after the boolean, so it might be an advantage to work out that texture on the smaller sphere to begin with before the boolean...makes it a lot easier than having to try and reach around inside later on. |
Post by frootee // Nov 6, 2007, 1:36pm
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frootee
Total Posts: 2667
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well I think the question is, How do you subtract the smaller sphere, if it is already completely encompassed by the larger sphere? It sounds like it cannot be selected for the boolean operation.
One other thing to consider with the shell tool: You can go inside the shell, and paint the inner polygons after the operation.
Yes interesting topic!
Later,
Froo |
Post by butterpaw // Nov 6, 2007, 1:49pm
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butterpaw
Total Posts: 831
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I agree about the planning ahead and applying the appropriate material first, and if I knew anything about materials... I would.. but I will have saved this in all stages.. so that backing up to do that a redoing should not be too painful ^_^
I already have a growing set of notes with location coordinates, sizes and degrees of rotation of all items so far (in this umteenth incarnation of the item), and items are also saved as objects, so I could rebuild from my plans. ... and I would not be surprised if it becomes necessary! :p ^_^ |
Post by Jack Edwards // Nov 6, 2007, 2:38pm
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Jack Edwards
Total Posts: 4062
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Another idea that would avoid the whole issue with booleans, would be to create two spheres, one larger than the other. Flip the normals on the smaller one. Glue the two objects together. Move the smaller one inside the larger one. Use the mesh collapse plug-in to make them one mesh. ;)
-Jack. |
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