Simulationism, also known as modelism, is an ideological movement and school of micropatriology (opposite from secessionism) pointing a convergence between micronationalism and the hobby of simulating countries. Therefore, inside modelist thinking, there a clear line that separates micronational activity and "macronational" business.
Rejection of secessionism
Simulationist thinkers often reject the idea of micronational independence, or secessionism. Prominent simulationist Parker I asserts that the secessionist goals, namely to achieve statehood, are "impossible." Through rejecting the possibility of secession, a simulationist must pursue other goals in regards to maintaining their micronation.
The rejection of secessionism is not universal among simulationists, however. While a central school of simulationist thought created by Parker I tends to preach actively against secessionism, some simulationists are more accepting of the secessionist community. The idea of simulation is not necessarily in-congruent with the ideas of secessionism.
Chief among the goals cited by Parker I is the idea of micronations established for the purposes of personal enjoyment. Personal enjoyment is deep rooted among micronations, with prominent nations such as the Aerican Empire and Molossia founded upon these principles. The simulationist school of thought advocates for the simulation of real world activities on the micro level, such as micronational warfare. Through its imaginary war against East Germany or its simulation war fought with Kickassistan, Molossia demonstrates the simulation of macronational dynamics in the micronational world for the purposes of enjoyment.
Simulationists typically seek to attain the goal of political experience through micronationalism. Due to the high amount of micronationalists interested in politics and political activity, the aspiration of becoming a future politician is common among micronationalists. With that aspiration, simulationists seek to create a full simulation of running a nation in order to further political experience.
Simulationism is characterized by the simulation of a micronational nation-state to most accurately or most creatively represent the real world. There are varying levels of simulation, which causes simulationist micronations to vary widely when simply examining the minutia. Therefore it is difficult to determine the level of simulation or even if a micronation ascribes to simulationist beliefs at first sight.
Highly controversial among the characteristics of simulationism is the idea of micronational warfare. Some simulationists, most notably Parker I, seek warfare as a means of simulating the real world through war "play." It is for this reason that simulationist nations like Secundomia reject the Union against Micronational War as obstructing simulation.
The simulationist view of war "play" generated a large amount of controversy through mitropatriological spheres. Jacob Tierney of Renasia critiqued the practice as "spitting in the graves" of fallen soldiers in macronational warfare. Simulationist warfare supporters rejected this view, claiming that micronational warfare can carry a respectful tone.
The reality of simulationist micronations varies widely. Many simulationist nations, such as Secundomia, rely on real events perpetrated by real citizens to create a level of simulation. This kind of simulationism doesn't always achieve blanket levels of simulation of the real world.
Other simulationist nations can rely on fake or inflated numbers of citizens, and wholly invented events. Most notable among these nations was Erusia. The downfall of many of these nations is a failure to be honest about the level of simulation occurring. When citizens are invented or even whole nations invented, a micronation lacking honesty is typically shunned from micronational communities. Nations inflating numbers and events that publicly acknowledge their inflations are less likely to be rejected by a community.
A central type of simulationist micronationalism lies within the hobby of conworlding. These types of micronations present themselves through spheres such as Micras. Conworlding goes a step further than inflationist nations and simulates entire worlds, cultures and histories. Conworlding begins to blur the line between micronationalism and pure imagination. As a form of simulation it can achieve extremely advanced levels of political and cultural simulation. This makes it essentially the pinnacle of simulation.
Simulationism tends to also simulate the cultural development of a micronation. One way a micronation can achieve this cultural simulation is by synthesizing a language, thus cutting the corners of macronational cultural development. Conlangs are created by one or a group of people working together with the intent of creating a language. In simulationism they can be employed to develop a simulated culture, further advancing the level of simulation.
A center of much micropatrological debate is the conflict over micronational "seriousness." Noted secessionist Trace Fleeman says that "serious [...] micronationalism [...] aim[s] at being recognized as sovereign nation." This view denounces simulationism as a less serious version of micronationalism.
Simulationists have sought to dissipate this view. Parker I cites the goals of Political Experience and personal enjoyment as serious goals. Additionally, he denounces the idea of secessionism as a serious form of micronationalism, calling it "deluded." 
This conflict over seriousness is rooted in the belief of one micronation more truly desiring the goal of becoming an independent nation than another. The conflict delves into the depths of micropatrology, asking whether or not a micronation should desire independence. Simulationists tend to believe that a micronation, by definition, should not seek or desire true independence from their macronation.
Simulationism as an ideology is as old as micronationalism itself. More recently, however, in the 2011 and 2012 it was revived as a major political movement by Secundomian politician Parker I. This was developed as a reaction to the prevalence of secessionist prejudice in the MicroWiki Community. The movement was revitalized primarily to increase the acceptance of micronational warfare and to undermine the feeling of superiority that was on the rise at the time. Parker I, despite a decrease in activity, still advocates for the movement in 2013.