I'm currently working on an application where I need to do some visualization, and the most complicated thing I'll be doing is displaying point-like objects.
Anything beyond that is complete overkill for my purposes, since I won't be doing anything but drawing point-like objects.
That being said, what would be the simplest solution to my needs?
The simplest is probably to use WPF 3D. This is a retained mode graphics system, so if you don't have huge needs (ie: special shaders for effects, etc), it's very easy to setup and use directly.
Otherwise, a more elaborate 3D system, such as XNA, may be more appropriate. This will be more work to setup, but give you much more control.
I recommend you take a look on Microsoft XNA for C#
Are they to be rendered as true points or as spheres? (where you see the 'points' that are closer using the visible size of the sphere as a reference.) In the former case, I would recommend simply multiplying the appropriate transformation matrices yourself to project the points to your viewing plane, rather than using a full-blown 3D engine (as you're not rendering any triangles or performing lighting/shading)
For some theoretical background on 3D projection to a 2D plane, see this Wiki article. If you use XNA, it has Matrix helper functions that generate the appropriate transformation matrices for you, even if you don't use it for any actual rendering. The problem becomes very trivial for points, as there are no normals to consider. You simply multiply the composed View Projection matrix by each point, clip any points that lie outside the viewing frustrum (i.e. behind the viewing plane, too far away, or outside the 2d range of your viewport) and render the points in X,Y. The calculation does you give feedback as to how 'deep' each point is relative to your viewing plane, so you could use this to scale or color the points appropriately, as otherwise it's very difficult to quickly understand the 3d placement of the points.
Related
I'm new to Unity and I'm making a car racing Game. Now, I'm stuck at some point. I was looking for some solution of my problem, but couldn't succeed.
My problem is:
When I run my game on my phone, it sticks badly because whenever there are several buildings in front of the car camera, like one building behind another building, it lags. Reason for this is there are so many vertices and edges at that time, So the Car Camera is unable to capture all that stuff at same time.
How do I preload the 2nd Scene while loading 1st Scene?
I am using Unity free version.
In graphics programming, there is a common routine to simply don't draw objects that aren't in the field of view. I'm sure Unity can handle this. Check link: Unity description on this topic
I'm not hugely knowledgeable about Unity, but as a 3D modeller there's a bunch of things you can do to improve performance:
Create a simplified version of your buildings with fewer polygons for use when buildings are a long way away. A skyscraper, for example, can be as simple as a textured box.
If you've done that already, reduce the distance at which the simpler imposters are substituted for the complex versions.
Reduce the number of polygons by other means. A good example is if you've got a window ledge sticking out of the side of a building, don't try and make it an extension of the body. Instead, make it a separate box, delete the facet that won't be seen, and move it to intersect with the rest of the building.
Another good trick is to use bump maps or normal maps to approximate smaller features, rather than trying to model everything.
Opaqueness. Try not to have transparent windows in your buildings. It's computationally cheaper to make them just reflect the skybox or a suitably blurred reflection imposter. Also make sure that the material's shader is in Opaque mode, if it supports this.
You might also benefit a little from checking the 'Static' box on the game object, assuming that buildings aren't able to be moved (i.e. by smashing through them in a bulldozer).
Collision detection can also be a big drain. Be sure to use the simplest possible detection mesh you can - either a box, cylinder, sphere or a combination.
So I am making all my models is Blender and then exporting it to .fbx format using the File ->Export and then checking off XNA Strict Options. This works just great, except that when I put my model in XNA, it has been stretched along the up-down axis and it is always the same scale. No matter how much I scale it in Blender, it is always the same size in game. Any ideas? Also, I'm not sure if this is related, but if I have a model with multiple parts, it will only show one part of it. Any help is appreciated!
I am more familiar with 3ds max than blender, but if this was happening in max I would know what's going on so I'll say it in case Blender works in a similar fashion.
When you modify something in a 3d modeling app (like scaling the model on a particular axis), it does not actually change the positions of the vertices like you may think. It only creates a transform matrix that can be applied to the original vertex positions at render time to make it appear the way you expect.
So when you import the model into Xna, you are importing the model with it's unscaled vertex positions and all the transform matrices it takes to render the model the way you would expect it to. But you have to apply those transforms in your Xna code or the model wont appear the way it did in your modeling app. (the issue you are having)
The way you apply the transforms is by calling the Xna Model.CopyAbsoluteBoneTransformsTo(Matrix[]). Make sure you do not call Model.CopyBoneTransformsTo(Matrix[]), you need the one with the word 'Absolute' in it.
Here is a tutorial that shows how to implement that method: http://msdn.microsoft.com/en-us/library/bb203933(v=xnagamestudio.40).aspx
I need to be able to generate a 3D perspective from a bunch of 2D images of a pipe.
Basically... We have written software that interprets combined data from laser and sonar units to give us an image slice from a section of pipe. These units travel through the pipe and scan the inside of the pipe every 100mm.
All of this is working great. My client now wants to take all these 2D image slices and generate a 3D view so they can "travel" through the pipe looking at defects etc.. that are picked up by the scans. We can see the defects in the 2D images but there can be hundreds of images in a single inspection - hence the requirement to be able to look through the pipe.
I am doing this in VS2010 on the .NET 4 platform in C#.
I am honestly clueless as to where to start here. I am not a graphics developer so this is all new territory to me. I see it as a great challenge but need some help kicking off - and a bit of direction.
Any help appreciated :)
Mike
Well, every 10cm isn't very detailed.. However, you need to scan the pixels of the pipe, creating a list of closed polygons, then just use a trianglestrip to connect one set to the next, all the way down the pipe.
Try to start with very basic 2d instead of full blown 3d rendering - may be good enough. Pipe when you look at it from inside can be represented as several trapeze. Assuming your images are small cylinder portions of a pipe - map each stripe to trapezoids (4 would be good start - easy to position) and draw than in circular pattern. You may draw several stripes this way at the same time. To move back/forward - just reassign images to trapezoids.
If you need full 3d - consider if WPF would work, if not - XNA or some OpenGL library will give you full 3d.
You don't specify the context, 100mm sample intervals may be sparse (a 1m pipe) or detailed (10km pipe). Nor do you specify how many sample points there are (number of cross sections and size of cross section image).
A simple way to show the data is to use voxels where each pixel on a cross section is treated as a cube and adjacent samples form adjacent cubes (think Minecraft). The result will look blocky but as it's an engineering / scientific application this is probably preferable. Interpolating the model to produce a smooth surface may hide defects or make areas appear to be defective. Also, rendering a cross section through a voxel is a bit easier than a polygon surface.
I have never written any silverlight apps but I am looking to write a 3d viewer for earthquakes and have it run from my web site.
I would like to create a simple viewer so the user can change the "camera" ie their perspective. The view could contain up to 10,000 objects in the 3d space.
I want the ability to quickly view this - I have seen this on a Power Basic application and want to do this for the web.
I have a current web site at http://canterburyquakelive.co.nz for earthquakes in Canterbury New Zeaalnd and I want to learn the basics so that it can be more interactive.
I want to say for example (to start) place 2 objects in a "space" that I can define and move the camera in real time.
The system must support up to 10,000 objects in the end of the day.
Each object can be a simple circle - no need for special pixel shaders
I am unsure of the exact functionallity of the system at the moment so if I can find a tutorial that allows me to place someone (a circle) into a 3d world (space) and change the camera that would be good.
Any ideas appreciated - there seems to be so much about 3d and silverlight that I may be getting lost in the "gloss" of new features where I need some basics and I can learn and adapt over time.
** Added comment + image **
Basically I am waiting to create a page that look like this using Silverlight. But I am open to any technology.
I've never done 3D in silverlight so I can't exactly answer your question as asked but in general to display geographic markers in a 'real' 3D terrain is quite involved. At a minimum you're probably looking at:
Obtaining binary height data files (last time I looked, NASA gives this away)
Reading and interpreting said files to get 'bitmap' height data
Choosing and dealing with projections (e.g. UTM)
Deciding how to tesselate your bitmap height data
If you want it textured you'll need to also obtain satellite data for that, again converting or processing it to account for projection.
You could ignore the terrain height, but that may not simplify things depending on how 'bumpy' your terrain is.
For a pre-defined small enough area, you could perhaps pre-author a 3d model of the terrain in some 3D package but displaying your markers will still require a projection from long/lat into your 3D space, and you'll still need to know terrain height (unless you do mesh collision with the static model).
Rendering the markers is pretty straightforward by comparison, choose from:
Use a 3D model e.g. a 'pin head' (simple but not always visible)
Render a regular n-gon with 'viewer facing' polygons (resolution independent but maybe ugly)
Render a quad with a circle texture on it (low poly but what size texture to choose?)
There are probably libraries that do some or all of this for you, so if you are set on rolling your own then some of the things I've mentioned could form the basis for your search.
However, given what you've described of your site and situation I suspect you'd be better off avoiding all that work by using a pre-existing solution. E.g. the Google Earth API.
You could consider 3D web plugins that -granted- take you away from Silverlight but that might speed up your development process. I'm thinking in particular of e.g. the Blender 3D web plugin. I can understand the need to write your own viewer, but think twice before you re-invent the wheel. Good luck!
I am going to make a game like XNA example game "Platformer1" which comes with the XNA. But I need longer levels which doesn't fit in the screen (like Super Mario levels). How can I manage this kind of level? Do I need to use a 2d camera that follows the sprite? If I do this way how can I load the level? I am a bit confused and I am not sure if I could explain my problem clearly. Hope someone can help?
The tutorial based on Platformer Starter Kit in MSDN has a step Adding a Scrolling Level which guides you through creation of longer levels. The tutorial is very detailed, I highly recommend it.
I couldn't find the tutorial in the section for XNA Game Studio 4.0, but differences should be minimal. According to the comment at the bottom of the page, all you need to change is replace
spriteBatch.Begin(SpriteBlendMode.AlphaBlend, SpriteSortMode.Immediate, SaveStateMode.None, cameraTransform);
with
spriteBatch.Begin(SpriteSortMode.Immediate, BlendState.AlphaBlend, SamplerState.LinearClamp, DepthStencilState.Default, RasterizerState.CullCounterClockwise, null, cameraTransform);
in the tutorial code.
If you want to create a side scrolling game, then I would look into parallax scrolling. A quick google/bing will help you find lots of tutorials. Also, another useful tip is to search YouTube for XNA videos has we a lot of posters share their source code .
Here is a link to Microsofts Parallax Scrolling.
Sounds like you have a few problems ahead of you.
But I need longer levels which doest'n fit in the screen(like super mario levels). How can I manage this kind of levels.
There are several ways to do this, but a fairly easy way would be to have a 2d array (or sparse array, depending on how large your levels are) of a class named Tile that stores info about the tile image, animation, ...whatever.
Yes, you'll probably want a "camera". This can be as simple as only drawing a certain range of that array or a more featured camera that uses transforms to zoom out and translate across your level.
Hopefully this will help get you started.
I've done a decent amount of work in XNA, and from my experience, there are 2 ways to draw a 2D scene:
1) Strictly 2D. This method is much easier, but has a few limitations. There is no "camera" per se, what you do is move everything underneath the fixed 2D "camera". I say "camera" in quotes because the camera is fixed (as far as I know). The upside is that it's easy, the downside is that you can't easily zoom in or out or do other camera effects.
2) 2D in 3D. Set up a 3D world with a 2D plane. This is more flexible, but is also more challenging to work with because you will need to set up a 3D world and 3D camera. If this is your first attempt with making a game, I would highly recommend against this method.
I'm really only familiar with the strictly 2D method, and you would want a list of map objects that have a 2D coordinate. You would also want to store which section of the map you are looking at, I do this with a Rectangle or Vector2 that stores this. This value would move forward as the character moves. You can then take your 2D map objects' coordinate and subtract the (X,Y) of the top-left of what you are looking at to determine an object's screen position. So:
float screenX = myMapObject.X - focusPoint.X;
float screenY = myMapObject.Y - focusPoint.Y;
An other thing to note, use floats or Vector2/3 to store locations, you may not think it's required now, but it will be down the line.
It might be overkill, but my SF project uses XNA to draw a Strictly 2D scene that you can move around: http://sourceforge.net/projects/asteroidoutpost/
I hope this helps.
Have a look at Nick Gravelyns tutorials. They helped me tonne when I was first starting out - Really really worth a look for learning a lot on 2D games.
All the videos are now on youtube here