I have used OrCad a fair bit.
I use it for university, it is part of many of my units.
The demo is free and is fully featured but "Limitations are in the size and complexity of the design."
I have not had any trouble with hitting these limits when I have been using the free version.
It has a large collection of libraries.
LTspice is another alternative, similar to the other answers here. It has a small, steep learning curve, but after a few hours you should have no problem to simulate simple circuits.
You can do DC, AC, transient analysis etc.. and offers a library with a good variety of basic components. Below are two screenshots from my installation on OSX, but it shouldn'...
I would definitely check out this guide, Open-Source Network Simulators. They all run on either Linux or BSD. The simulators included in the guide are,
VNX and VNUML
You can do that via Paypal Developer Tools.
Specifically with a Sandbox Test Account and the paypal API.
It will be from your end the same as a real paypal credit card transaction. I haven't used it with Java so I can't comment on any specific tricks to make it work best for that. If after reading those docs you get stuck at all I'd suggest asking a ...
I would suggest taking a look at the blender physics engine - specifically look for convex hull simulations. It is free and should allow you to do the sort of visualisations that you are looking for, The only down side is the steep learning curve but it is well worth the effort.
EdGCM provides a research-grade Global Climate Model (GCM) with a
user-friendly interface that can be run on a desktop computer. For the
first time, students can explore the subject of climate change in the
same way that actual research scientists do. In the process of using
EdGCM, students will become ...
The one that I know is Aimsun, which is defined as a traffic modelling software that allows you to model anything from a single bus lane to an entire region. It's a professional tool and I'm pretty sure it can do what you need.
There's also an Aimsun page on Wikipedia:
Aimsun software is used by government agencies, municipalities,
universities and ...
Netkit is the best suited tool for your opensource tool.
Netkit is an environment for setting up and performing networking experiments at low cost and with little effort. It allows to "create" several virtual network devices (full-fledged routers, switches, computers, etc.) that can be easily interconnected in ...
I think you are looking for Sikuli.
This tool will run at the first level to simulate a real user, whether on a webpage or a desktop application. I don't have a first user experience with this tool But in my previous company they have seriously considered it as the main testing tool for one of the projects and saw my colleges working on it.
It seems it ...
This was made possible by 2003 studies. The first paper includes some pictures. I couldn't find an avaible piece of software making use of this.
The relevant algorithm seems to be SMARDDA. Havn't found any graphic/publicly avaible implementation, so to my (informed) opinion this question has today no relevant answer. I'ld love to be proved wrong.
After using sketch up for a while I realized It does not offer the freedom I needed,such that to be able to properly view the inside of a building you have to cut out one wall. I found another program though, Sweet Home 3d which has the capability of staging virtual visit as well as drawing on predrawn picture layouts.
Although there are quite some Quadcopter kits on the market, and "how-to"s I don't think it is easy to create one from the scratch. Therefore I agree that first simulating the Quadcopter is a good start, although I am not sure until what detail you can simulate it (i.e. with the weights of the motors and rotors, etc).
You can use ROS (Robot Operating System)...
You have a couple of options:
If your main concern is speed and you don't care about testbench features, have a look at Verilator, which supports just the synthesizable subset of Verilog (up to the "more important features of Verilog 2005).
If you need a few more testbench features, try GPL Cver, but keep in mind that it only supports Verilog 1995 (with ...
You could take a look at traditional graphing tools such as:
plot.ly which does have some geographic plotting available
Bokeh also allows geographic plotting
Matplotlib with basemap can as well
But all of the above need quite a lot of work and generally are looking to display on a global or national scale.
I would suggest taking a look at QGIS which ...
You can use Proteus from Labcenter.
It is commercial software but with evaluation version you can create full schematic and simulate it but you can't save it.
The limitations are that it does not allow you to save, print or design your own microcontroller based designs (you can however write your own software programs to run on the existing sample design ...
There is pyTectnonics which should let you do your modelling for the plates and there are several python based hydrology GIS systems about you could possibly integrate them with the Blender Physics engine.
Able to model plate tectonics for non-earth worlds
3D view via blender
Free & Open Source
This one may be a solution for you, complex in design: Algodoo
It is free (the previous versions were not). It handles gears but many other automation tasks such as virtual robots and is targeted at schools. This one is easy to use since it is for teachers/students. There are videos on the site.
Recently I have been preparing myself to pass the CCIE R&S exam and I've found that
combination of GNS3 and Cisco IOU is very useful and could be suffusion, also if you going through study DC you can run titanium IOV over VMWare to simulate N7K, and sure you can use the image of n1000 to simulate the n1000 virtual switch top of UCS. So it really depends ...
There us jvisualvm which lets you monitor graphically the memory, performance and behaviour of a given JVM - since the JVM is itself a Virtual Machine it is its own best simulator. More information can be found on the developer site.
What you are looking for is software development prototyping software or "Rapid Application Development" this will allow you to quickly put together the User Interface or User eXperience UI or UX prototype to give to potential users to see if you have captured their design requirements.
A lot depends on the area that you are considering are you looking at:
Download and install VirtualBox.
Download a Ubuntu ISO, and install that in a VM.
In your Ubuntu VM, download, install, and run Cisco Packet Tracer. It is the gold standard for teaching routing and router theory.
Replace Ubuntu with Windows if you want, and have a license...
I would suggest trying Houdini. You can create an inflatable balloon object out of a mesh with any properties you desire. There is actually a beginners level tutorial that shows how to do exactly what you are talking about. An apprentice edition with very few restraints is available for free.
If you and/or your nephew are up for a rather steep learning curve then Blender 3D Modeller can make excellent 3D castles, with walk/fly-throughs, animations, and just about everything on your list other than AI driven attacks.
Blender itself is available 100% free for Windows, Mac & Linux. A little research online will also give you at least one blender ...
I'd recommend http://imunes.net/
It uses Docker for L3 nodes (Quagga in routers) and Open vSwitch for L2 nodes so basically you get "real" Linux machines connected with "real" switches. Note that it doesn't have any special support for bus or other topologies but you can use the GUI to construct those topologies.
Quite a steep learning curve but Blender 3D allows you to model things in 3D and includes a [physics engine] that allows a high degree of simulation for an example see here.
Free Gratis & Open Source
Can be used for a lot of other things up to creating games or movies
Lots of online tutorials, etc.
It may sound a bit strange but the Fire Dynamics Simulator a great tool for simulating heat and mass transfer within buildings. The fact that you won't be simulating combustion at all really just makes it easier(and faster). The is freely available, very well documented, has pretty readable code and includes visualization software.
I've used this a fair ...