We have collected a selection of common questions and topics related to LIME.
Q: I have a suggestion to improve LIME - is it ok to communicate it to the team?
We are always happy to receive your feedback on how to improve LIME. Just drop a message to firstname.lastname@example.org.
Q: How do I cite and acknowledge LIME?
Please reference the following paper when citing LIME:
Buckley, S.J., Ringdal, K., Naumann, N., Dolva, B., Kurz, T.H., Howell, J.A., Dewez, T.J.B., 2019. LIME: Software for 3-D visualization, interpretation, and communication of virtual geoscience models, Geosphere, 15(1): 222-235. doi:10.1130/GES02002.1.
In addition, if you find LIME useful for your work, we would appreciate acknowledgement of the software in presentations or publications based on LIME outputs.
Q: So, what are these Panel things anyway...?
In LIME, we use Panels as a catch-all term for integrating different sorts of images into the 3D scene. A Panel can be a simple image file dropped into 3D space. It might be a field photo, a log, subsurface dataset or geophysical section, interpretation panel, diagram, slides and much more... It might be a georeferenced image, such as a map, orthoimage or similar.
LIME can also project data (lines or models for example) to a blank Panel, as well as project any Panel onto a 3D model. It may take some time to get used to the concept, but Panels are an extremely flexible and creative way to build up your project - integrating many different data types as the basis of a virtual field trip.
Q: How do I import an image into the 3D scene?
We use Panels to add imagery into the 3D view. This makes a plane in 3D with the image file draped over.
To achieve this: choose Create Panel from the 3D Elements menu. In the Panel creation dialog, choose Image File as the type of Panel to create. Then all you need to do is Shift+Left Click on an existing 3D element to position the bottom left corner of the image in the 3D scene. The image will be placed to fit within the current viewport. Use the 3D draggers to move, rotate and scale the image to your desired position.
You can also use the "Helper planes" to place a Panel in empty space if you cannot click on any existing 3D data.
Q: How do I export a textured model from Agisoft MetaShape (formerly PhotoScan) for use in LIME?
Export model as Wavefront OBJ (*.obj). If the model is georeferenced, select the appropriate projected coordinate system (for example UTM, national grid or local coordinates). Models exported with a geographic coordinate system (i.e. lat/long) are not compatible with LIME at this time. For versions of LIME prior to 1.1, the Shift (offset) parameter must be set for the X and Y coordinates to reduce large coordinate values. This avoids “jitter” when navigating in 3D caused by graphics card precision. We recommend that the offset is still used for maximum compatibility with other 3D graphics software.
Q: Can I improve the texture resolution of a model built in Agisoft Metashape, prior to export to LIME?
Yes, by increasing the Texture count parameter when building the texture. Using the default Texture count (set to 1 in the screenshot below) will result in coarse, pixelated texture for larger models. Recommended value depends on your camera's image resolution, but can be 10 or more. It is recommended to keep Texture size at 4096 to be widely compatible on a range of hardware.
Q: How many triangles should be in a 3D model for use in LIME? And what about texture resolution?
Although modern computer hardware has improved massively from the early days when we were working with 3D lidar models (we pushed the limits with a few tens of thousands of triangles), so has the acquisition hardware and processing software! Today it is easy to generate massive 3D models based on hundreds or thousands of high resolution camera images, and consequently bring our computers to their knees in terms of performance - even with a high amount of RAM and a decent graphics card.
For standard machines (see our suggested minimum hardware spec), we recommend up to around 3 million triangles in a single model section. This value is indicative, as it also depends on the size and number of texture images (for textured models). Textured models come with a number of additional image files, which all need to fit in the graphics memory. So if a model has many triangles and lots of high resolution texture images then performance can suffer.
Fortunately, many 3D model processing software packages offer options to optimise the size of input point clouds, number of triangles generated, and resolution of output textures.
An even better way to deal with this is with tiled models (split up into a level of detail - LOD - hierarchy for fast streaming on demand). LIME's visualisation framework is designed for these models, so for large areas or high resolution datasets, this may be the only efficient way to load all your data.
Q: What sort of PC do I need to use LIME? Are we talking high-end machines?
We have put together a recommendation for a minimum specification (on this page) that should be easy to meet for modern laptops and stationary PCs. In short it means having enough RAM and a dedicated graphics card, such as from NVIDIA. LIME will run without the dedicated graphics card, though not all features may be supported, or performance may suffer.
Q: I’m using a laptop with integrated and dedicated graphics cards. How do I get the best performance out of LIME? (Legacy question: no longer relevant for LIME v2)
Modern laptops often ship with a dedicated high performance graphics card to run 3D graphics software, and an “integrated” card for general purpose usage (such as for document handling, playing movies etc). The graphics card drivers and operating system handle the switch between the two depending on which software is run. However, the OS does not always get it right, and you may need to override which graphics card is chosen to run LIME. For NVIDIA cards (recommended), the procedure is as follows (Windows 7):
Alternatively, LIME can be run on demand with the NVIDIA processor by right clicking on the software icon and selecting the NVIDIA processor under Run with graphics processor.
Recent optimisations mean that LIME v2 will automatically switch to the high perfomance graphics card on startup!