Jmc2obj Wiki


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Here ygsdgsdgDownload + Installation

You can download the program from this page: . Once you download the program, put it in a convenient place and simply double-click to run. You need to have Java installed to run this program. If the program doesn't run, but instead opens in an archiving application (e.g. WinRAR), make sure you are running it as a Java binary: right-click it, choose “Open with” and find “Java binary” or something similar. If this also doesn't work, or you don't have such an option, you can still try and run the program from the command line. Under windows, you can create a batch file (text file with the .BAT extension) in the same folder. On other systems, just open the terminal and change directory to the one where the application lies and run this command (change the .JAR file name to the one you have):

java -jar jMc2Obj-dev_rXXX.jar

To run the program with more ram you can also use this command:

java -Xms2g -Xmx4g -jar jmc2obj.jar

-Xms is the minimum ram, -Xmx is the maximum.

Main screenEdit

Once you run the program, you will be greeted with this screen:

Program main

The window consists of two main areas: a toolbar with buttons and input fields on the top, and the map preview area.

By default, a console window will also open. It will contain useful information on the progress of the program and what it is doing. This is mainly used for debugging purposes and logging errors, but it can safely be closed, and optionally set to not open when the program is next started. If there is an error, it will be forced back open, and it can be opened again manually with the "Open Console" button on the main screen.

Level selectEdit

All the way on the top, you will find a few input boxes that let you choose the world you want to load. You can either expand the list and choose the world from your default Minecraft saves list (if you have Minecraft installed) or type in the path to a world save folder (it is the folder that contains the level.dat file). Alternatively, you can also click the ”…” button on the left to run an Open folder dialog and choose one that way.

The field on the right side of the level select is the dimension selection. Dimension 0 is the normal world, -1 is the nether and +1 is the end. If you have mods installed, there may be even more dimensions available.

Once you choose the world you like simply click Load to open it.

Preview Options Edit

Fast render: Disables elevation shading, helps with speed a little bit, and is also useful for working up close with smaller selections.

Show chunks: Displays a line overlay of chunks.

Select Chunks: will automatically snap your selection region to the chunk lines.

Region selectionEdit

Once you have loaded your world, a map will display and automatically center at the last location of your character in game. This location is also marked with a red cross on the map. The green cross represents your spawn.

To navigate the map simply right-click and drag the map to move it around. Left-clicking and dragging will select the area you want to export. You can also select specific coordinates by using the Position 1 and 2 fields at the top. These actions can be remapped in the Settings dialog (click the Settings button). You can also zoom in and out by scrolling the mouse wheel.

You can also use the Goto button to type the X/Z location you want to go to instead of scrolling there using the mouse.

After selecting the area you want to export, you can also choose to export the world only between certain heights. The lower height is called the floor and the upper is called the ceiling. Floor and ceiling can be changed using the number fields at the top of the preview area. Altering this will also change the preview to reflect your chosen settings. If you are exporting a normal world it is often beneficial to export only slightly below sea-level (so set the floor to about 50) as this will save a lot of memory and most of the things below there are going to be invisible in the final render.

Whenever you interact with the map preview, the information on the left will change to display the current chosen value. You can review them and fine-tune your selection by hovering the mouse over the edges or the corners of the selection and click-dragging those. You can also move the whole selection by click-dragging inside it.

Once you have selected your area you want to export, click the Export and move on to the next section.

Other informationEdit

Below the preview area you will see a few progress bars. These are actually memory monitors. The right one shows the ratio of total memory reserved from the maximum allowed memory (512 MB by default). The left one is the ration used from what is reserved (i.e: the left one). The same values are written in the little box in the left corner, T is the total memory (right bar) and F is the free memory (“inverse” of the left bar). This is purely for debugging purposes, to see how the program works on different computers, so we can tune it where possible.


When the program starts it will automatically try to connect to a server to check the newest version of the program. If a new version is found, the program will display a message and highlight the Update button. After you click the button a small window will open where you can check exactly what version is available. If you click Update in that window the application will briefly close and a new window showing the progress of the download will appear. After the download is complete the application will immediately start again.

Export optionsEdit

After you click “Export selection”, you will see the export panel appear:

Export Screen

The Map scale option allows to change the unit size in export. By default, one Minecraft block is saved as one unit in size. You can change that here: 0.5 will make the world 2 times smaller, 2 will make it 2 times larger. Most modern 3D program will allow you to change this later, so most of the time you don't need to worry about this and can leave it at its default 1.0 value.

Offset is a really useful feature. It is used to move the exported world to a different location. The Center setting will center the exported world around the center of the selected region. Most of the time you will want to use this option. Choosing None will perform no centering. This is useful if you want to export several OBJ files of the same world and have them import in their “natural” locations. The last option allows you to set the offset manually.

The "Select blocks to export" button will open a window like this:

SelectBlocks Window

Here you can specifically select and deselect all of the blocks you want to export. You can also search for blocks to change instead of scrolling through the list. The "Select All" "Deselect All" "Toggle All" buttons will only affect the blocks shown on the list, i.e: if you search for "wood" and press "De-select All" any block that contains "wood" in the name will not be exported. If you have a few block selection settings that you would like to use multiple times, you can save them in a preset.

Render unknown blocks will export blocks that are not in the blocks.conf file (more on that later).

Render world sides and bottom lets you include or exclude the sides and the bottom from the export. Excluding it will save a substantial amount of memory, while including it will make the walls visible if you intend to present them in your renders.

Render biomes will include the biome information in the final export. The biome information can be configured in the blocks.conf by changing the biome attribute of the material used.

Render entities option allows to include or exclude entities from the export. Entities include objects like paintings, vehicles (minecarts, boats, etc), mobs and so on. Each entity belongs to a certain chunk and has an absolute location. That is why some entities may appear to hang in the air, outside of the exported region.

Convert all ore blocks to stone... does just that.

Create separate object for each material allows you to generate a separate object for each Minecraft material type. This is useful in some 3D programs to modify the materials more easily.

Create separate object for each chunk makes a separate object for each 16×16 group of blocks. This option can be combined with the one above.

Create separate object for each block - IS NOT RECOMMENDED! Only use if your export area is extremely small and you really need control over each block in the area, like for animation.

Optimize mesh will GREATLY reduce file size and increase efficiency, however, does not work well with separate .obj per material or block, and will break using a single material and single texture (see below).

Do not allow duplicate vertices removes duplicate vertices from the export. This procedure is time and memory consuming and may crash the program in exceptionally large exports. Most of the time it is useful, however, as it saves a bit of memory on the output and makes the export more consistent.

The Use single materials for the whole export option creates an OBJ file with only one material. The material is named "minecraft_material" and is referenced only once at the start of the file. This option can be combined with other options, but it is recommended to be used with Separate object per material only and is designed for use with the option below.

Use single texture file option is related to the texture export options mentioned below. If you export all your textures to a single file, you must define the UV file location in this option. This will also be set automatically if you set the texture options as such (see below).

Use last save location and name will do just that if you have already made a previous export with the program.

Once you set up all the options, clicking Export will prompt you for a save location and name (if use last save location and name is not checked) and then will start exporting the map. It may take a while, depending on the size of the selection and you can stop the procedure at any time by pressing the stop button.

Texture optionsEdit

After exporting the map (or before is you wish to use a single texture file), you will also need to export the textures. You will need to do this only once per export folder, so no need to go there too often.

The default location for saving the textures will be the “tex” sub-folder of your OBJ save folder. This is the location linked in the MTL file as well, so it is not recommended changing this setting, unless you change the MTL file as well.

Pre-scaling textures can improve the quality of renders in certain programs, but will make the files substantially larger.

Exporting alpha channels is necessary for certain programs so it is recommended to leave this selected, unless you are trying to save space (it doubles the amount of files).

You can also choose to export all your textures to a single file here. This can simplify the texturing in some programs, but has to be used with care. If you intend to use this, make sure you also check the Use single texture file option in the export options above. It will automatically be checked for you and the .UV file should automatically link as well. If not, you can select it manually.

Export separate light blocks is optional if you intend to use GI in your renders. These are just blocks that "should" emit light.

Finally, you can choose to export directly from Minecraft or use a custom texture pack. Once you click one of those buttons, the program will immediately export the textures.

You can also export a .obj file created from the clouds image in Minecraft or from a texture pack.


To open the settings window, simply click on the “settings” button at the top of the main window. (to be revised)


There are only a few options available, so far. First two options change how you can interact with the map. The options allow you to bind three different key types (left/right/middle) with optional shift modifier to one of the two actions - select and drag. Depending on what you are used to, you can choose a configuration that feels most intuitive. E.g., people that use Blender may be used to having dragging linked to the right button and selecting to left. On the other hand, online maps are usually dragged using the left mouse button, and selecting is intuitively bound to shift-clicking.

The language option allows you to change the language for the whole interface. In the version r263, only 3 languages are available: English, German and Polish, with German being only partially done. Volunteers are welcome with implementing other languages. Changing the language requires restarting the program. This can be achieved by clicking the “Restart program” button on the bottom.

Use system browser may or may not work on certain Operating systems, but is at least confirmed working on windows. It basically just uses the system browser you are used to instead of the native java browser. If you have issues, turn this off and restart the program.

Restore to factory settings button deletes all saved user preferences. This includes all the saved states in the various export/texture options and files/paths history.

Using the OBJ with your 3D programEdit

Once you have exported your world into an OBJ file you can then import it into any 3D program that supports this format. Here are a few options:

Advanced configurationEdit

If you want to get most out of the program you might also check the following articles:

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