This page lists some known bugs and issues which may arise with the Road Architect tool.
Road Incline Problems:
Strange road narrowing has been observed when using very steep inclines. This should be avoided.
Vertical Static Meshes:
Static meshes (such as lamp posts, bollards, fences, etc) often point directly upwards. This can look strange on roads with either inclines or lateral rotations, and may not be desired behaviour. If this causes problems, the user can remove these lanes from the road profile.
Decals Not Rendering Correctly:
Sometimes the decals which are laid on to the mesh (or laid on to the terrain, if meshes are not used) will not render correctly and may even not appear at all. This is a known bug and should be fixed in future. There is currently nothing which can be done about this problem.
Avoiding large curvatures may help solving the issue, but may not always. If this issue is encountered, we advise the user to experiment by moving nodes around to see if the problem disappears.
Unusual Mesh Poses:
Sometimes (especially with inclines or lateral rotations on the road), the static meshes (such as crash barriers, concrete barriers, etc) can appear to have the wrong pose. The mesh components may even overlap/clash.
Road Folding:
If the curvature is too tight for the road, folding can occur. This is where the road appears to fold back over itself on one side. This is more common with wider roads, and should be avoided. It can produce rendering problems.
This is caused due to the fact that each lane poly line is projected laterally from the road centerline.
UV Texture Stretching:
For thin lanes in particular, sometimes the texture on the lane can appear stretched. This can also occur on road lanes at areas of large curvature, and possibly in some other cases.
For lane types such as lamp posts, where this happens, the lane width can be reduced to zero. This should remove the problem there, but note that the adjacent lanes should be of similar height so as to ‘hold’ the lamp post meshes in a visually-natural way.
Linkage Overlapping:
When linking roads where the curvature difference is large (between road A and road B), gaps can appear between the link road and one/both of the roads.
Moving the resolution slider of the road to a smaller number can help, since as the resolution increases, the spline of the link road would tend towards having perfectly-matching tangents. This limit is unachievable in practice however.
We recommend to keep the curvature difference between roads to be linked, under some threshold.
Visualization Z-Clashing:
Z-clashing can occur in both the visualization (eg in Edit Mode) and in the meshes/decals themselves (in Finalize Mode).
In the visualization, lines are visible which should not really be seen from the perspective of the camera. This should be fixed in upcoming versions.
With meshes/decals, sometimes the user may witness flickering at road joins. This is due to overlap. To minimise overlap, the curvature of the joining roads/adjacent roads can be minimized.
Sinking Decals:
There is a known bug when laying decal on top of roads which appear on terraformed terrain and/or steep cliff-like terrains. The decals (eg lane edge decals, centerlines, etc) will typically appear on the road as expected, but a copy will also appear on the steep terrain below. Sometimes decals (or parts of decals) may miss the road and sink below to either the terrain or a road which may be below the expected road. This problem needs more investigation.
Too-Tight Terraforming:
Currently, the terraforming is quite tight to the road. This can cause problems at road ends or at the edges of roads. Decals may even appear to fall off the road.
More work needs to be done with the terraforming algorithms, to alleviate this.
Bumpy Terraforming:
A bumpy appearance has also been witnessed when terraforming the terrain to some roads (typically where there is lateral camber changes). The terraforming algorithms require some work to minimize this problem. For now, we recommend either to use meshes in these case (which should mask the issue) or for terraforming to be done on roads with less lateral camber.
Import Irregularities:
When importing OpenDRIVE files (.xodr), the roads can appear different to how they should be. This is most noticeable where roads join. Sometimes road lanes in OpenDRIVE files are collapsed to have zero width. In this tool, linear interpolation attempts to smooth this rather than chopping it. Further work needs to be done to resolve this problem.
Other importing problems may appear, especially on larger/more complicated .xodr files. This may appear as badly-interpreted road widths or other artifacts.
Internally, we only support road half widths (from centerline to edge) up to 30 meters. Some .xodr files contain roads which have larger half widths than this.
