Why is the osgb generated by contextcapture small and not merged?

When we want to show the model results of the models in adjacent areas after modeling for many times, or when the data in the same area needs to be modeled in blocks because of too much data, we need to combine the models to output a complete result.

The principle of CC model merging

When 1. CC generates a model, no matter what the projection coordinate system is, there is an origin (similar to the 0,0 point in CAD, which can also be considered as the coordinate origin of the local coordinate system), and the vertex coordinates in the generated model triangular mesh are all relative to this coordinate origin. You can set the origin of coordinates when submitting reconstruction, as shown in figure 1:

2. When 2.CC generates the model, due to machine configuration (memory, cpu, graphics card) and other factors, when the amount of data is large, the model has to be divided into blocks. After selecting a block, the size of the block will be set according to the machine configuration. Using the block method and block size, CC will automatically calculate the name of each block. For example: Tile_+004_+003. And the name of the block is constructed from the coordinate origin. The result after blocking is shown in Figure 2:

3. Based on the above principle, as long as the coordinate origin is consistent and the block size is consistent, the model generation results can be directly merged (provided that the block size is consistent).

Model merging method

1. Merge folders directly. This method needs to confirm the following information:

It is necessary to determine whether the coordinate origin of the merged model is consistent, the inspection method, the advanced option in figure 1, or the metedata.xml file in the same level directory of the model;

You need to determine whether the block size is consistent, check the method, TileSize in Figure 2, or load the data into LocaSpaceViewer and simply measure it with the measurement function. (Note: If the joint edge is not very tight, or there is a certain interval between two adjacent models, as long as the coordinate origin is the same, even if the block sizes are different, as long as there are no duplicate tile numbers, they can be merged. )

2. When using CC to export the model, set the same boundary (which can be achieved by importing kml range), so that all the numbers will not be repeated, and the exported model can be directly merged into the folder.

3. The generated model files in osgb format can also be merged, and all the model vertex coordinates are relative to the coordinate origin, just need to translate the coordinate origin of the model. This method involves the modification of the model itself and is not recommended. Conventional operations can read each vertex of the model and then modify it by writing code.

4. If you just want to see the merged effect or display it together, you can directly load two oblique photographic data with lsv. When generating lfp, you can offset, rotate and adjust the height by setting the coordinate origin, so that the adjacent two models can be displayed better.

5. None of the above methods can completely guarantee the edge stitching problem. If you want to block and merge the results after block processing, you need to complete it through the control point. According to the requirements of control points, each block should contain an appropriate number of control points, and the overlapping degree of photos in the block is more than 0.5 times of the height of 65438+ route.

Q: If you have generated models for the whole area and found that only a small part of the models are not satisfied, and then re-shoot, do you need to regenerate all the models at this time?

A: No, just import the reshaped photos into the successfully completed block, and then resubmit three empty photos. After the completion of empty three, keep the previous generation parameters unchanged, and only submit unsatisfactory tiles. Then directly copy the newly generated tiles folder to the last model result to replace the old tiles.