project-navigation
Personal tools

Author Topic: Design: Tech tree  (Read 26937 times)

Offline BTAxis

  • Administrator
  • PHALANX Commander
  • *******
  • Posts: 2607
    • View Profile
Design: Tech tree
« Reply #15 on: April 12, 2006, 04:27:26 pm »
I have created an example research tree design:



A rectangualr box represents a research topic. A rounded box represents an external event. An arrow represents dependency. Joined dependencies (lines converging into one at a bubble) mean a research topic is dependant on one or more topics and/or events. If a number is given next to the joint, that means at least that many prerequisites have to be satisfied before the topic can be researched.

Hoehrer seems to think there is redundancy and reverse-dependency in this tree, but there really isn't. There are no loops in it, and everything in this tree must be specified, or prerequisites will be implicit, which is bad. Comments?

Hoehrer

  • Guest
Design: Tech tree
« Reply #16 on: April 13, 2006, 03:30:06 pm »
I'll have a look at this later.
To be honst, i don't want to see the research system for some time now, i've coded and designed it for quite some time already.
The current system is a working one (if not as complex as wanted, but working) and i'll start extending it when i feel like it again.

Keep your dependencies as they are, but don't expect them to be implemented soon.

Quote
Hoehrer seems to think there is redundancy and reverse-dependency in this tree, but there really isn't. There are no loops in it, and everything in this tree must be specified, or prerequisites will be implicit, which is bad.

The whole discussion was useless because we talked about two different things:
"How the research system works NOW" VS "How the research system may work in the FUTURE."
In the first case you just don't need to define anything that is 'collected' as an "xxx retrieved" event, because the tree solves that for you .. remember my second OO drawing, where i inserted the whole bunch for arrows that lead back to an 'already researched item'? That wasn't researched, because you can only enter the 'loop' if there is an item collected. I didn#t draw these lines in my first mockup, because they are just confusing.

You drew the second case, a _future_ system.
 And _I_ never stated there is reverse-dependency in YOUR drawing, i tried to explain that it was in the (MY) current system.

Werner

Offline BTAxis

  • Administrator
  • PHALANX Commander
  • *******
  • Posts: 2607
    • View Profile
Design: Tech tree
« Reply #17 on: April 13, 2006, 08:15:12 pm »
Yeah, I found that out after I made the above post.

Hoehrer

  • Guest
techtree in SVN
« Reply #18 on: April 24, 2006, 11:25:38 am »
I've uploaded a merge of all techtree descriptions that have been posted in the various forum-threads to SVN:

trunk/src/docs/techtree.txt

Especially the research times and some of the dependencies need a bit of work and the obligatory grammar and 'sane' check ;)

Please do not change major things (or generally put alot of work into it) before discussing the changes here.

Werner

Offline XCOMTurcocalypse

  • Rookie
  • ***
  • Posts: 91
    • View Profile
Design: Tech tree
« Reply #19 on: May 02, 2006, 01:02:56 pm »
Tech Proposal :


After researching all Plasma Techs we could enable a research of "Appliance of Plasma Engines in General"

This could increase the speed of existing Aircraft for a cost of time and money for modification

A few coding shouldn't hurt.And it could add spice.

jagreen

  • Guest
Design: Tech tree
« Reply #20 on: July 15, 2006, 10:13:56 pm »
I see the Alien Technology in this way.

Some texts are the uses in real life, or the hipotesys about that technologies.

The text marked with "In terms of game:", are the implications of those technologies ingame.


Technology:

Genetic Engineering Technology

   -Clonation
   -Cell Regeneration
   -Terraforming
   -Computers & Comunications (With biological components).

Chemistry Technology

   -Phisic Impromevents
   -Letal Gas
   -Self Destruction (The body of the alien explote, with a chemistry explosion)

Nano Technology

   -Cell Regeneration
   -Plague (nanobots infectation and transmition)
   -Weapons miniaturalization (i dont know if it well traduced "Miniaturalization" ^_^, but this technology is really hard to implement in game i think). =/

Hologram Technology

   -Self camouflage
   -Ships camouflage
   -Base camouflage

PsyTechnology

   -Psy weapons
      -Mind Control
      -Mind Damage
   -Psy armours
   -Psy implants
      -Mind Control
      -Mind in Blank
      -Mind leach (Steal information to implanted one)

Geotechnology

   -Fast Buildings (base upon quartz crystal growth)
   -Fast Bases (base upon quartz crystal growth)
   -Ships structure (base upon quartz crystal growth)

Laser Technology


In the real life:

A laser (from the acronym Light Amplification by Stimulated Emission of Radiation) is an optical source that emits photons in a coherent beam. The back-formed verb to lase means "to produce laser light" or possibly "to apply laser light to".

A dye laser used at the Starfire Optical Range for LIDAR and laser guide star experiments is tuned to the sodium D line and used to excite sodium atoms in the upper atmosphere.

Laser light is typically near-monochromatic, i.e. consisting of a single wavelength or color, and emitted in a narrow beam. This is in contrast to common light sources, such as the incandescent light bulb, which emit incoherent photons in almost all directions, usually over a wide spectrum of wavelengths.

Laser action is explained by the theories of quantum mechanics and thermodynamics. Many materials have been found to have the required characteristics to form the laser gain medium needed to power a laser, and these have led to the invention of many types of lasers with different characteristics suitable for different applications.

The laser was proposed as a variation of the maser principle in the late 1950s, and the first laser was demonstrated in 1960. Since that time, laser manufacturing has become a multi-billion dollar industry, and the laser has found applications in fields including science, industry, medicine, and consumer electronics.



Uses

    Main article: Laser applications

At the time of their invention in 1960, lasers were called "a solution looking for a problem". Since then, they have become ubiquitous, finding utility in thousands of highly varied applications in every section of modern society, including consumer electronics, information technology, science, medicine, industry, law enforcement and the military.

In 2004, excluding diode lasers, approximately 131,000 lasers were sold world-wide, with a value of US$2.19 billion [5]. In the same year, approximately 733 million diode lasers, valued at $3.20 billion, were sold.

The benefits of lasers in various applications stems from their properties such as coherency, high monochromaticity, and capability for reaching extremely high powers. For instance, a highly coherent laser beam can be focused down to its diffraction limit, which at visible wavelengths corresponds to only a few hundred nanometers. This property allows a laser to record gigabytes of information in the microscopic pits of a DVD. It also allows a laser of modest power to be focused to very high intensities and used for cutting, burning or even vaporizing materials. For example, a frequency doubled neodymium yttrium aluminum garnet (Nd:YAG) laser emitting 532 nanometer (green) light at 10 watts output power is theoretically capable of achieving a focused intensity of megawatts per square centimeter. In reality however, perfect focusing of a beam to its diffraction limit is somewhat difficult.
Lasers used for visual effects during a musical performance. (A laser light show.)

Consumer electronics

Communication

In consumer electronics, telecommunications, and data communications, lasers are used as the transmitters in optical communications over optical fiber and free space. They are used to store and retrieve data from compact discs and DVDs, as well as magneto-optical discs. Laser lighting displays (pictured) accompany many music concerts.


Science

In science, lasers are employed in a wide variety of interferometric techniques, and for Raman spectroscopy and laser induced breakdown spectroscopy. Other uses include atmospheric remote sensing, and investigation of nonlinear optics phenomena. Holographic techniques employing lasers also contribute to a number of measurement techniques. Laser (LIDAR) technology has application in geology, seismology, remote sensing and atmospheric physics. Lasers have also been used aboard spacecraft such as in the Cassini-Huygens mission. In astronomy, lasers have been used to create artificial laser guide stars, used as reference objects for adaptive optics telescopes.

Medicine

In medicine, the laser scalpel is used for laser vision correction and other surgical techniques. Lasers are also used for dermatological procedures including removal of tattoos, birthmarks, and hair; laser types used in dermatology include ruby (694 nm), alexandrite (755 nm), pulsed diode array (810 nm), Nd:YAG (1064 nm), Ho:YAG (2090 nm), and Er:YAG (2940 nm). Lasers are also used in photobiomodulation (laser therapy) and in acupuncture.

Industry

In industry, laser cutting is used to cut metals and other materials. Laser line levels are used in surveying and construction. Lasers are also used for guidance for aircraft. Lasers are used in certain types of thermonuclear fusion reactors. Lasers are also used extensively in both consumer and industrial imaging equipment. The name laser printer speaks for itself but both gas and diode lasers play a key role in manufacturing high resolution printing plates and in image scanning equipment.


Road safety

In law enforcement the most widely known use of lasers is for lidar, to detect the speed of vehicles.
The surface of a test target is instantly vaporized and bursts into flame upon irradiation by a high power continuous wave carbon dioxide laser emitting tens of kilowatts of far infrared light. Note the operator is standing behind sheets of plexiglass which is naturally opaque in the far infrared.
Enlarge
The surface of a test target is instantly vaporized and bursts into flame upon irradiation by a high power continuous wave carbon dioxide laser emitting tens of kilowatts of far infrared light. Note the operator is standing behind sheets of plexiglass which is naturally opaque in the far infrared.

Military

Military uses of lasers include use as target designators for other weapons; their use as directed-energy weapons is currently under research. Laser weapon systems under development include the airborne laser, the advanced tactical laser, the Tactical High Energy Laser, the High Energy Liquid Laser Area Defense System, and the MIRACL, or Mid-Infrared Advanced Chemical Laser.


In terms of game:

   -Holographic
   -Scanners
   -target designators
   -Laser Defenses (For destroy missiles, ships, etc...)
   -Laser Weapons



Plasma Technology

In physics and chemistry, a plasma is typically an ionized gas, and is usually considered to be a distinct phase of matter in contrast to solids, liquids, and gases because of its unique properties. "Ionized" means that at least one electron has been dissociated from a proportion of the atoms or molecules. The free electric charges make the plasma electrically conductive so that it responds strongly to electromagnetic fields.

This fourth state of matter was first identified in a discharge tube (or Crookes tube), and so described by Sir William Crookes in 1879 (he called it "radiant matter"). The nature of the Crookes tube "cathode ray" matter was subsequently identified by English physicist Sir J.J. Thomson in 1897, and dubbed "plasma" by Irving Langmuir in 1928, perhaps because it reminded him of a blood plasma. Langmuir wrote:

    "Except near the electrodes, where there are sheaths containing very few electrons, the ionized gas contains ions and electrons in about equal numbers so that the resultant space charge is very small. We shall use the name plasma to describe this region containing balanced charges of ions and electrons."

Plasma typically takes the form of neutral gas-like clouds or charged ion beams, but may also include dust and grains (called dusty plasmas).They are typically formed by heating and ionizing a gas, stripping electrons away from atoms, thereby enabling the positive and negative charges to move freely.


# Plasma applications

    * Fusion power
          o Magnetic fusion energy (MFE) — tokamak, stellarator, reversed field pinch, magnetic mirror, dense plasma focus
          o Inertial fusion energy (IFE) (also Inertial confinement fusion — ICF)
          o Plasma-based weaponry


In terms of game:

   - Magnetic fusion field (personal, ships and bases)
   - Inertial fusion energy (Energy for ships, weapons, etc)
   - Plasma Weapons.


Tachyon Technology

   The Tachyon Technology is very similar to Particle Accelerator (we can use it like a simil =))

   Tachyon Technology:
   Although our engineers not fully understand the principles of altering the tachyons on a subatomic level, they were able to reproduce the tachyon accelerator technology. Apparently the tachyons are given a defined spin inside the accelerator so they are able to interact with any material. They still tend to infiltrate easily through any known armor and lose their particle energy not before a penetrating distance of about 10 cm. Therefore a soldier hit by a tachyon charge suffers only minor superficial injury but is heavily wounded in his viscera.

   Particle Accelerator:
   A particle accelerator is a device that uses electric and/or magnetic fields to propel electrically charged particles to high speeds. There are two types: linear (i.e., straight-line) accelerators and circular accelerators.


   In the next few decades, the possibility of black hole production at the highest energy accelerators may arise, if certain predictions of superstring theory are accurate (Scientific American, May 2005). If they are produced, it is thought that black holes would evaporate extremely quickly via Hawking radiation. However, the existence of Hawking radiation is controversial.It is also thought that an analogy between colliders and cosmic rays demonstrates collider safety. If colliders can produce black holes, cosmic rays should have been producing them for aeons, and they have yet to harm us. However, this is also controversial; some have suggested possible models in which black holes might be created by colliders but not cosmic rays.

   In terms of game the aliens can use Tachyon Technology for:
      -Interestelar travel (Using Black holes)
      -Tachyon Weapons (soldier weapons, base weapons, and ships weapons)
      -Tachyon Defenses


Antimatter Technology


In particle physics, antimatter is matter that is composed of the antiparticles of those that constitute normal matter. If a particle and its antiparticle come into contact with each other, the two annihilate; that is, they may both be converted into other particles with equal energy in accordance with Einstein's equation E = mc2. This gives rise to high-energy photons (gamma rays) or other particle–antiparticle pairs. The resulting particles are endowed with an amount of kinetic energy equal to the difference between the rest mass of the products of the annihilation and the rest mass of the original particle-antiparticle pair, which is often quite large.

Antimatter is not found naturally on Earth, except very briefly and in vanishingly small quantities (as the result of radioactive decay or cosmic rays). This is because antimatter which came to exist on Earth outside the confines of a suitable physics laboratory would almost instantly meet the ordinary matter that Earth is made of, and be annihilated. Antiparticles and some stable antimatter (such as antihydrogen) can be made in miniscule amounts, but not in enough quantity to do more than test a few of its theoretical properties.

There is considerable speculation both in science and science fiction as to why the observable universe is apparently almost entirely matter, whether other places are almost entirely antimatter instead, and what might be possible if antimatter could be harnessed, but at this time the apparent asymmetry of matter and antimatter in the visible universe is one of the great unsolved problems in physics. Possible processes by which it came about are explored in more detail under baryogenesis.


Posibles uses of that technology:

Medical imaging

Antimatter-matter reactions have practical applications in medical imaging, such as positron emission tomography (PET). In positive beta decay, a nuclide loses surplus positive charge by emitting a positron (in the same event, a proton becomes a neutron, and neutrinos are also given off). Nuclides with surplus positive charge are easily made in a cyclotron and are widely generated for medical use.


Antimatter as fuel

In antimatter-matter collisions resulting in photon emission, the entire rest mass of the particles is converted to kinetic energy. The energy per unit mass is about 10 orders of magnitude greater than chemical energy, and about 2 orders of magnitude greater than nuclear energy that can be liberated today using nuclear fission or fusion. The reaction of 1 kg of antimatter with 1 kg of matter would produce 1.8×1017 J (180 petajoules) of energy (by the equation E=mc²). This is about 35 times as much energy as nuclear fusion of the same mass of hydrogen (fusion of two kg of hydrogen produces 5.2×1015 J), or as much energy as burning 6.2 billion liters (1.6 billion US gallon) of gasoline (the combustion of one liter of gasoline in oxygen produces 2.9×107 J).

Not all of that energy can be utilized by any realistic technology, because as much as 50% of energy produced in reactions between nucleons and antinucleons is carried away by neutrinos, so, for all intents and purposes, it can be considered lost.

The scarcity of antimatter means that it is not readily available to be used as fuel, although it could be used in antimatter catalyzed nuclear pulse propulsion. Generating a single antiproton is immensely difficult and requires particle accelerators and vast amounts of energy—millions of times more than is released after it is annihilated with ordinary matter, due to inefficiencies in the process. Known methods of producing antimatter from energy also produce an equal amount of normal matter, so the theoretical limit is that half of the input energy is converted to antimatter. Counterbalancing this, when antimatter annihilates with ordinary matter, energy equal to twice the mass of the antimatter is liberated—so energy storage in the form of antimatter could (in theory) be 100% efficient. Antimatter production is currently very limited, but has been growing at a nearly geometric rate since the discovery of the first antiproton in 1955.[3] The current antimatter production rate is between 1 and 10 nanograms per year, and this is expected to increase to between 3 and 30 nanograms per year by 2015 or 2020 with new superconducting linear accelerator facilities at CERN and Fermilab. Some researchers claim that with current technology, it is possible to attain antimatter for US$25 million per gram by optimizing the collision and collection parameters (given current electricity generation costs). Antimatter production costs, in mass production, are almost linearly tied in with electricity costs, so economical pure-antimatter thrust applications are unlikely to come online without the advent of such technologies as deuterium-tritium fusion power. Many experts, however, dispute these claims as being far too optimistic by many orders of magnitude. They point out that in 2004, the annual production of antiprotons at CERN was several picograms at a cost of $20 million. This means to produce 1 gram of antimatter, CERN would need to spend 100 million trillion dollars and run the antimatter factory for 100 billion years. Storage is another problem, as antiprotons are negatively charged and repel against each other, so that they cannot be concentrated in a small volume. Plasma oscillations in the charged cloud of antiprotons can cause instabilities that drive antiprotons out of the storage trap. For these reasons, to date only a few million antiprotons have been stored simultaneously in a magnetic trap, which corresponds to much less than a femtogram. Antihydrogen atoms or molecules are neutral so in principle they do not suffer the plasma problems of antiprotons described above. But cold antihydrogen is far more difficult to produce than antiprotons, and so far not a single antihydrogen atom has been trapped in a magnetic field.

Several NASA Institute for Advanced Concepts-funded studies are exploring whether the antimatter that occurs naturally in the Van Allen belts of Earth, and ultimately, the belts of gas giants like Jupiter, might be able to be collected with magnetic scoops, at hopefully a lower cost per gram.

Since the energy density is vastly higher than these other forms, the thrust to weight equation used in antimatter rocketry and spacecraft would be very different. In fact, the energy in a few grams of antimatter is enough to transport an unmanned spacecraft to Mars in about a month—the Mars Global Surveyor took eleven months to reach Mars. It is hoped that antimatter could be used as fuel for interplanetary travel or possibly interstellar travel, but it is also feared that if humanity ever gets the capabilities to do so, there could be the construction of antimatter weapons.



Three Theories

The CPT theorem asserts that antimatter should attract antimatter in the same way that matter attracts matter. However, there are several theories about how antimatter gravitationally interacts with normal matter:

    * Normal gravity - Standard theory asserts that antimatter should fall in exactly the same manner as normal matter.
    * Antigravity - Initial theoretical analysis also focused on whether antimatter might instead repel with the same magnitude. This should not be confused with the many other speculative phenomena which are also called 'antigravity'.
    * Gravivector & Graviscalar - Later difficulties in creating quantum gravity theories have led to the idea that antimatter may react with a slightly different magnitude.



Antimatter in terms of game:

   - Antigravity (Antigravity Ships, Bases, personal armour).
   - Tractor beams.
   - Energy (For weapons, bases, ships...).
   - Scanners (For ships for example).
   - Weapons (Weapons bassed in antimatter technology).

Technologies with armamentistic implications:

Arcane Technology:

Some pieces of Arcane Technology would be great for win the war ;)

Offline Bandobras

  • Captain
  • *****
  • Posts: 586
    • View Profile
Design: Tech tree
« Reply #21 on: July 16, 2006, 12:11:07 am »
Wow. Cool texts. BTW, I would like to announce that the current tech tree for UFO:AI now resides on the wiki at [[Research]].

Could you look at it and decide how this relates to you proposals? Then either discuss it here or add appropriate texts to the discussion pages on the wiki? In general, we are currently striving to get 2.0 ready ASAP so big changes are not a priority, as opposed to correcting and enriching the currently implemented tech descriptions.

jagreen

  • Guest
Design: Tech tree
« Reply #22 on: July 16, 2006, 05:27:39 am »
Hehehe, yes sry ^_^, my mind sometimes carry me to fantastic places. I will try to enrich the existing ones sure =)

jagreen

  • Guest
Design: Tech tree
« Reply #23 on: July 16, 2006, 05:32:12 am »
better, we can discurs about some of them & the existing ones. Or any others ideas are too wellcome =D

Offline Bandobras

  • Captain
  • *****
  • Posts: 586
    • View Profile
Design: Tech tree
« Reply #24 on: July 16, 2006, 10:33:48 am »
As you wish. "Traduced" is "translated" or "interpreted" in English, AFAIK. All the future techs I currently omit. Is your intention to put the "In the real life" and "Uses" texts in game? Or is it only food for thought in tech design? BTW, I've just swiped your "Charged ion beams" for a wiki description. :) The tachyon section is a bit disappointing. I though I will get something also from there for uor current descriptions...

jagreen

  • Guest
Design: Tech tree
« Reply #25 on: July 16, 2006, 04:22:28 pm »
I think that some of the technology would be great to be based on real hipotesies, or existing uses.

Those descripcions above the labels "In the real life" & "uses" only mean that those text, are the real description of the technology. Not the ingame description, because the people will bore reading that amoung of text. =D

Would be great that we can use those text for make a short description of each technology.

jagreen

  • Guest
Design: Tech tree
« Reply #26 on: July 16, 2006, 05:13:30 pm »
I really like your research tree, but how about in this way?

Based in my previous post:
- Magnetic fusion field (personal, ships and bases)
- Inertial fusion energy (Energy for ships, weapons, etc)
- Plasma Weapons.

In this approximation the more expecific technologies need more requirements. I will try to do a example:



---Alien Plasma Theory
Needs: a plasma item (with only one you can study the Alien Plasma technology)
Allow: Alien Plasma Weapons, Alien Plasma Energy, Alien Magnetic Plasma Fields.

--Alien Plasma Weapons.
Needs: a plasma weapon (only one of the differents weapons).
Allow: You can use weapons dropped by aliens or captured, Alien Plasma Pistol research , Alien Plasma Rifle research, Alien Plasma Mine research,...

-Alien Plasma Pistol.
Needs: a plasma pistol.
Allow: You can produce plasma pistols.

-Alien Plasma Rifle.
Needs: a plasma rifle.
Allow: You can produce plasma rifles.

-Alien Plasma Mines.
Needs: a plasma mine.
Allow: You can produce plasma mines.



--Alien Plasma Energy.
Needs: A Alien Inertial Fusion Energy Source (like a ship Fusion Propulsor, a plasma magazine, Plasma Defenses Energy source...
Allow: You can use Alien Fusion Energy (the captured ones), Alien Plasma Propulsor research, Alien Plasma Magazine Research, Alien Plasma Defense Energy Generator Research.

-Alien Plasma Propulsor.
Needs: A Alien Plasma Propulsor.
Allow: You can produce Alien Plasma Propulsors

-Alien Plasma Magazine.
Needs: A Alien Plasma Magazine.
Allow: You can produce Alien Plasma Magazines.

-Alien Plasma Defense Energy Generator.
Needs: A Plasma Defense Energy Generator.
Allow: You can produce Alien Plasma Defense Energy Generator.



--Alien Magnetic Plasma Fields.
Needs: A Alien Magnetic Plasma Fields (personal, ship, base).
Allow: You can use Alien Magnetic Plasma Fields captured, Personal Magnetic Plasma Field research, Ship Magnetic Plasma Field research, Base Magnetic Plasma Field research...


-Alien Personal Magnetic Plasma Fields.
Needs: A Alien Personal Magnetic Plasma Field.
Allow: You can produce Personal Magnetic Plasma Fields.

-Alien Ship Magnetic Plasma Field.
Needs: A Alien Ship Magnetic Plasma Field.
Allow: You can produce Alien Ship Magnetic Plasma Fields.

-Alien Base Magnetic Plasma Field.
Needs: A Alien Base Magnetic Plasma Field
Allow: You can produce Alien Base Magnetic Plasma Field.


That could be a great COMMON way of research tree structure. :P

Offline Bandobras

  • Captain
  • *****
  • Posts: 586
    • View Profile
Design: Tech tree
« Reply #27 on: July 16, 2006, 05:27:33 pm »
Why research separately Alien Plasma Weapons? And what for Alien Plasma Magazine? Is that so I can use alien weapons with their magazines (reload, too?) but cannot produce mine? Hmm, not a bad idea... What do you think, folks? This would require a change to the engine (so post-2.0), because right now everything you can use, you can also purchase (produce).

This is all I can get from your post right now (for 2.0 or shortly after). The other uses of plasma are not yet planned (the tree in the "unimplemented" part is an old draft, so I don't even know if plasma plays a part there).

jagreen

  • Guest
Design: Tech tree
« Reply #28 on: July 16, 2006, 05:41:08 pm »
Yes you have to research Alien Plasma Theory, and later Alien Plasma Weapons, for can USE a Alien Plasma Weapon.

For product a Plasma Rifle for example you need to research:

Alien Plasma Theory, Alien Plasma Weapons, Alien Plasma Rifle.

And for Ammo for that Plasma Rifle:

Alien Plasma Theory (already reseached), Alien Plasma Energy and Alien Plasma Magazine.

Thats all =)

jagreen

  • Guest
Design: Tech tree
« Reply #29 on: July 16, 2006, 05:47:27 pm »
The secret of that aproach resides in no give to the player a lot of aliens aliens weapons and magazines, in each mission, because "IF THEY CAN USE AND THEY FIND FRECUENTLY THOSE ITEMS WHY PRODUCE IT?"

Only a short number of those items (for study and for a little use) :)